Rejuvenating Hardwood & Softwood Floors

RENOVATING WOODEN FLOORS

A natural timber floor can look beautiful if it’s sanded, sealed and polished and it’s cheaper than laying new carpet.

Timber floors which have been covered with carpet or lino for years, or have varnish or paint which is wearing thin, can be renovated and given a long lasting protective finish. First identify the type of floor you have.

Softwood floorboards: You may have plain, softwood floorboards – either square-edged or tongued-and-grooved planks up to 25mm thick and 150 to 230mm wide, nailed to the floor joists.

Hardwood flooring: Another type is a decorative hardwood floor. Jarrah, Oak, Mahogany and Teak are the most commonly-found woods, although other more exotic types are also used, but rare.

There are several kinds of hardwood floor. The first consists of slim hardwood planks that are either nailed to the floorboards beneath or are held in place by a system of metal clips. Cheaper versions use veneered ply wood strips instead of solid timber.

The second type is hardwood block flooring, often referred to as parquetry. This consists of small blocks of wood up to 230mm long and 75mm wide which are usually laid in a herringbone or basket-weave pattern. Older or more expensive types are blocks up to 25mm thick, bedded in a bitumen adhesive. Cheaper imitations are again veneered.

The third type is the mosaic panel – a floor tile made up by gluing small fingers of wood on a backing sheet to make up a panel 300 or 450mm square. These are laid like any floor tile, either on an adhesive bed or loose on top of a special underlay.

Deciding on the treatment the usual treatment involves sanding the floor with a powered sanding machine to remove the old finish and expose clean, fresh wood ready for sealing and polishing. Any solid wood floor can easily tolerate this, but if the surface is only a veneer then power sanding with a coarse abrasive could go right through it. In this case, gentler methods such as a hand-held belt or orbital sander are advisable.

BEFORE YOU START

Check the floor structure for signs of woodworm or rot. If you find wood worm, tackle it by lifting the floorboards and spraying water-based woodworm fluid over the affected surfaces before re-laying the boards. If you find rot, call in an expert to assess the problem; DIY treatment is often possible, but may not be effective if dry rot is present.

If the floorboards need lifting during preparation you could put in under-floor insulation. This can be done by stapling plastic netting between the joists to support fibre glass (bats) insulation, or by resting strips of rigid polystyrene insulation on nails driven into the sides of the joists. With suspended timber ground floors, make sure that air bricks are clear, so the under-floor void is well ventilated, or rot can get a hold.

TOOLS AND EQUIPMENT

The only specialist tools you’ll need for this job are two powered sanding machines, which you can hire. The larger machine is called a drum or floor sander; It resembles a cylinder lawn mower and drives belts of abrasive round a large drum. It has a built-in sawdust extraction unit. The smaller machine is needed for sanding the parts the larger one cannot reach; you may be offered a belt or a disc type. The former Is better because it will not leave scratch marks across the grain.

When you take delivery of the machines, make sure that you are shown exactly how to operate them, and get plenty of abrasive sheets and belts in coarse, medium and fine grades. Buy or hire a face mask at the same time, so you don’t choke on the sawdust. Safety goggles and ear muffs are also a good idea, though not essential.

SAFE SANDING

When using a floor sander, always wear a face mask so you don’t inhale the clouds of fine dust which always seem to escape the machine’s dust bag. Wear goggles and ear muffs.

Common sense hints:

1. Seal the door with masking tape to keep dust out of the rest of the house, and open windows for ventilation.
2. Don’t wear loose clothing; close fitting overalls are best. Protect your hands with gloves when handling the abrasive sheets and belts. Always unplug the machine when changing them.
3. Keep the sander’s electric cord out of harm’s way by draping it over your shoulder.
4. Never start the machine with the drum in contact with the floor, or it will snatch away from you uncontrollably. Stop it immediately if the abrasive tears, or you may jam the drum.
5. Lastly, don’t let children touch the machines under any circumstances.

Next Prepare Softwood Floors

Getting a good surface: – With softwood floors, using a nail punch and hammer, check that all nail heads are punched at least 3mm below the surface. Remove any tacks which have been used to hold down any previous flooring. Fix any loose boards by driving in shorter flooring nails close to existing nail positions, to minimise the risk of piercing hidden pipes or electric cables. Use deeply-countersunk screws if warped boards keep pulling the nails up.

Filling large gaps: – If there are substantial gaps between boards, fix them with slim strips of timber planed to width, glued and hammered into place. Gaps everywhere suggest that it would be far quicker to lift all the boards, to re-lay them so they butt together tightly, and to add one or two new boards as necessary to make up the gap when all the old boards have been replaced. Check the measurements of your floorboards before buying new ones: there is a range of standard sizes, but if you have old or unusual boards, you may need to order planks cut to size.

Replacing rotten boards: – If you find boards that are split or otherwise badly damaged, replace them with new boards. To lift tongued-and grooved boards, first cut through the tongues along each edge with a pad saw (a long slim saw which looks rather like a knife) or a powered jigsaw. Beware of electric cables and pipes running under the boards. Then nudge the board up from one end with a crowbar or similar lever, using a scrap of timber to protect the end of the adjacent sound board. Cut the new board to fit and nail it in place. If it’s not as thick as the others, add cardboard packing under it.

Turning the boards: – If the surface is badly damaged, for example through repeated layers of linoleum being tacked down or badly stained, you can try turning over the floorboards. The undersides will be marked where they cross the joists, but apart from that they should be in a better condition (woodworm and rot permitting) than the top surface. Lift just one or two boards first to check their condition.

Cleaning up: – Finally, sweep the floor. Then make sure you’ve got all your tools and equipment with you, close the door to the rest of the house and seal round it with masking tape to stop dust from spreading everywhere. Open the room windows for ventilation, and to help the dust clear as you work.

PREPARING HARDWOOD FLOORS

With hardwood floors, check for loose blocks or panels, and stick down any that you find with flooring adhesive. Hardwood flooring is often secret nailed in place, particularly the narrow plank types and some of the mosaics. If sections have worked loose they should be re-fixed in the same way, by secret nailing through the tongue into the floor joist. Watch out for pipes and electrical installations.

NOW WERE READY FOR SANDING THE FLOORBOARDS

Starting to sand: – Fit a coarse abrasive sheet to the sander, plug in and switch on to test that it’s working. Then start sanding with the machine in one corner of the room. The arm is to work diagonally to begin with, to ensure that all the boards are sanded level with one another, so start by heading for the opposite corner of the room. Then turn around and run back over the same strip. Continue sanding the whole floor diagonally in this way, taking care not to damage skirting’s as you reach the end of each run. Replace abrasive sheets as they become worn.

Getting a good finish: – Next, change to medium-grade abrasive and sand the floor parallel with the board direction, again going over each strip in both directions. Work as close to the skirting boards as you can without scoring them with the side of the machine. Then switch to fine abrasive and repeat the whole process again. Empty the dust bag regularly into heavy-duty plastic refuse sacks. It’s also a good idea to vacuum the floor from time to time to cut down on the amount of fine dust flying around. Also change the filter in your face mask regularly so it doesn’t get clogged up.

Down to details: – You can now tackle the edges, and any other parts that the drum sander couldn’t reach, using the belt or orbital sander. Work through coarse, medium and fine grades of abrasive paper. Finish off by hand sanding any bits that have been missed.

Cleaning up: – When you’ve finished sanding, sweep and vacuum-clean thoroughly to remove as much dust as possible. Pay attention to joints between the boards, and to the corners. Then use a clean cloth soaked in white spirit – to wipe over the boards.

Try a different type of finish on your new floor: –

If you don’t like the yellowing effect of varnish, experiment with one of these techniques.
Bleach the wood first with a proprietary wood bleach or a mixture of oxalic acid and methylated spirit. Alternatively, prime the boards with a 50/50 solution of white emulsion paint and water, rubbing it into the grain.

Any water-based solution will raise the grain slightly, so apply this before the final sanding. You can also add 10 per cent white eggshell paint to 90 per cent varnish.

SANDING HARDWOOD FLOORS

A floor of hardwood timber planks does not usually require quite such drastic treatment as a softwood floor. You should find that simply sanding up and down the planks with first medium and then fine abrasive is sufficient to remove the existing finish and any slight irregularities. Don’t forget to check that the floor is not veneered – you may have to lift a splinter of wood from a corner of the room with a penknife.

A hardwood mosaic (block) floor should also be easy to tackle. The main problem is deciding in which direction to sand the floor. You should avoid sanding across the grain of the wood. So, a herringbone pattern should be sanded up and down the room, while a basket-weave pattern should be sanded diagonally. You will then have sanded the grain of the wood diagonally (as close as you can get to sanding with the grain, which gives the best finish). Depending on the condition of the floor, only medium and fine abrasives should be necessary.

Any hardwood mosaic borders round the edge of the room should be sanded with a belt or orbital sander.

SEALING THE FLOORS

Filling holes: – Now with clean, freshly sanded wood exposed, it is time to fill nail and screw holes, plus any other gaps between the floorboards which have not been filled with wood strips. Use wood filler, adding wood dye to the filler if necessary to match the shade of the wood more accurately. Use wood bleach on any deep stains that have not been removed by the sanding. When the filler is hard, sand down locally and wipe up dust with a rag using white spirits as before.

Adding colour: – You can change the colour of the floor if you wish by using wood dyes. Follow the manufacturer’s instructions carefully; in most cases a single coat of dye is wiped on to the floor with a lint-free cloth, working along the grain.

Test the effect of the dye on an off-cut first, then working over a larger area to develop the application technique. The porosity of wood varies, so test the dye on new wood to see that it matches. Also check the finished effect by varnishing the test pieces. After you have done the whole floor, wipe with a clean dry cloth to remove surplus dye.

Apply varnish: – Thin the first coat of varnish with about 10 per cent white spirits, when used on softwood, use it straight from the tin on hardwood. If the wood is porous, it may be quicker to wipe the first coat on with a cloth, rather than using a brush. Allow it to dry for as long as the manufacturer recommends; then sand the surface lightly with fine abrasive on a sanding block, and wipe over with a rag to remove the dust. Apply two further coats using a 75mrn brush, cutting in at the edges with a smaller one. Sand as before. Always work back towards the door so you can get out easily.

Using coloured varnish: – You can also apply coloured varnishes. For an even finish, it is best to prime the boards with clear varnish first, as above, before building up two or three coats of coloured varnish. A final protective coat of clear varnish can be added for extra protection.

Polishing it up: – Finish the job by polishing the floor surface – either by hand or using a hired floor polisher. Make sure that any rugs or carpets laid over the floor have non-slip pads on their undersides.

Property Inspection Perth WA

From $450/Call Relevant Office

We are your eyes, when the builder informs you that your new home is almost complete and is ready for a “ Practical Completion Inspection ” that is when you contact our office and arrange for one of our inspector to attend with you and the builders supervisor and systematically go through the home and document. All unsatisfactory or incomplete items of workmanship will be identified in order for the builder to rectify these items within the contract designated time frame, for you to move into your new home. 

The builder/supervisor will do all the note-taking, as we go through the home together, inside & outside. You must inform your builder in writing of our attendance. 

Call Peter 0418 948 760 – Davide 0424 305 175 for relevant pricing.

Building Inspection Service Perth

It is essential that all recommendations made in the building and pest inspection reports be addressed well. The building inspection report is a very essential factor as it is a detailed property survey done by building experts.

09a – Dilapidation SurveyHourly Rate/Call Relevant Office

If you are a professional or Owner builder, and your prospective home is surrounded by an existing building, you should allow and provide for a Dilapidation Report. These reports check and record digitally) existing damage, prior to the start of building a home or commercial project, so that your neighbours cannot blame existing damage on your current works.

Call Peter 0418 948 760 – Davide 0424 305 175 for relevant pricing.

09b – Workmanship ReportHourly Rate/Call Relevant Office

You may be concerned of, what you perceive to be, unsatisfactory workmanship that is currently under construction of your home. That is when you contact our office and arrange for one of our inspector to assess the workmanship to date. A written report is complied using digital photos or you can meet our inspector on site for a verbal interpretation and commentary.

Call Peter 0418 948 760 – Davide 0424 305 175 for relevant pricing.

09c – Building Maintenance ReportHourly Rate/Call Relevant Office

When your maintenance on your home is due, that is when you contact our office and arrange for one of our inspector to assess and verify the maintenance items to be carried out by the builder.

Call Peter 0418 948 760 – Davide 0424 305 175 for relevant pricing.

09d – Drone Roof InspectionsHourly Rate/Call Relevant Office

Inspections are carried out with the help of a drone, where areas are physically hard access.

Call Peter 0418 948 760 – Davide 0424 305 175 for relevant pricing.

09e – Thermal Imagingfrom $650

Thermal Imaging is the visual way of identifying where there is insulation missing, electrical circuitry is overheating and where there a moisture seepage’s where a normal visual inspection would not identify these issues – again we able to arrange this service.

Call Peter 0418 948 760  or Marios 0410 189 689  for relevant pricing.

09f – Home Indemnity Insurance ReportCall Head office

If you are an Owner Builder and need to sell your Owner built home before 7 years is up, then you will require by law, to provide your purchaser an Home Indemnity certificate. To obtain this you will need to approach a reputable broker, who in turn will require you to produce a Home Indemnity report.

Call Peter 0418 948 760 or Davide 0424 305 175 for relevant pricing.

09g – Energy Reportsfrom $350

with the new legislation in place to have the most energy efficiency in a home – we are able to arrange a energy report letting you know exactly where energy is wasted (leaking)

Call Peter 0418 948 760  Davide 0424 305 175  for relevant pricing.

09h – Re-inspection or Re-certificationHourly Rate/Call Relevant Office

If a report has identified items to be repaired, how can you be sure that they have been correctly repaired, well, we can re-inspect or re-certify the job in question.

Call Peter 0418 948 760 – Davide 0424 305 175 for relevant pricing.

Pre Purchase Building Inspections Perth

As per AS4349.1-2007 (Appendix A)
From $450.00

The Pre-purchase Structural is the foundation of all our inspections and was designed primarily for the budget-minded person and is a must for all types of homes. It covers the fundamental performance of the Primary Load Bearing (structural) componentry of a building, where, if structural deficiencies are discovered, these can be costly to repair. This is also one of the least expensive written reporting formats and offers a sense of security. The report is short and concise and is ready for immediate e-mailing.

Call Peter 0418 948 760 – Davide 0424 305 175  for relevant pricing. 

Roof Repairs In Preparation For Winter

Now that winter is drawing closer it is time to prepare our roof and drainage system for the onslaught of those wet and blistery days.

A checklist would be a handy item to have so here is one:

A) Clear all gutters of debris

Clear all gutters of debris that is leaves and even build up of dirt collected over the years, as all those particles can firstly clog up the downpipe pipe entry and cause a build up of water in the gutter and secondly when the gutter dries out debris will hinder the drying process allowing rust to form in suspect areas.

Also check to see if the gutter has been backplated (see diagram) if not then overflow of water into the eaves, under the conditions mentioned above is very likely. This can be rectified by replacing the removed portion of metal from the gutter, efficiency of the gutter is reduced by 50-60 percent if the back of the gutter is not reinstated.

Sometimes downpipes can also get blocked, it is wise to flush them out especially if they are connected to soakwells. Never seal the join between the down pipe and the shoe where it runs into a soakwell, because if the soakwell ever loses its capacity then it can overflow at ground level at the join and not at gutter level.

For gutters to last longer the inside cam be painted with a bituminous paint which will effectively double the life of the gutter.

B) Valley gutters flashing and other protrusions

It is also wise to check that all protrusions are still water tight, that is the seal between lead flashings and the pipes (vents & Flues) are still water tight if not seal them with a bead of paintable Silicone. All metal components should always be protected to slow down the deterioration process and all Lead components should be painted so as not to cause accelerated rusting to the galvanised metal components on a roof such as gutters and downpipes.

Valley gutters should also be kept free of leaves and debris which can quite ,easily get caught especially if the free valley space is less that 100mm (4”). The water as it rushes down from the tiles onto the valley will get caught up in the leaves and debris and soon it will act as a dam and tend to overflow along the sides especially as over a period of time the LIPPED VALLEY ENDS (see “End on View” diagram) of the valley gutter have been clogged with dirt, crimped down by the weight of the tile or flattened down by holding down nails, it is very time consuming to carry out and rectify this but is well worth it if water ingress is a problem along valley lines.

Another problem is that valleys can overflow due to the sheer rush and volume of water deposited during a storm on steeply pitched roofs. Fitting baffles will redirect the flow of water and eliminate this problem.

So that we all understand what we are talking about enclosed is also a part cross sectional diagram of a typical roof and eaves.

How to cure Rising Damp

No problem is so wide spread nor so misunderstood as rising damp. Probably every building built before 1900 has a damp problem in some degree and thousands of dollars are spent in repairs.

In many cases the cure is worse than the disease; ill-conceived treatments may in fact increase the problem and could decrease the real estate value of the building.

On top of this many renovation practices can cause problems where they may not have existed previously.
Expensive and good looking renovations can turn into disaster areas by not allowing for moisture flow in old walls.

The symptoms of wall dampness are easily recognised: musty smell, deteriorating paint and plaster. The moisture behaves like a wick and in fact is called wick action, it literally rises up the wall, like kerosene rises in a wick on the kerosene lamp. There comes a point where the damp cannot rise any further due to natural ventilation causing it to dry out this area is called the tide mark and is quite visible, at that point the drying out process is the fastest and mineral salts are deposited as visible marks on the wall. This tide mark is usually at about 900mm above floor level.

The first step in rectification is to source the cause, the damp proof course which is usually made out of lead or galvanised iron or even bituminous material, which is imbeded between the brick coursing, in the hope of preventing the damp rising, may have deteriorated over the years. But more often the problem is elsewhere.

The most logical and essential consideration to the prevention of rising damp is keeping the ground on which the building is located as dry as possible. That is achieved by diverting any discharged water well away from the building and its foundations, it is also essential to check gutters, drains and down pipes for hidden leaks that may not always be obvious.

If the floor structure is timber then the underneath should be well ventilated using the natural cross ventilation system available, by means of vent grilles installed on the perimeter walls, at every 1.8 meters is desirable.

If it is a concrete raft slab construction, then the damp usually rises on the perimeter walls and is almost always due to bridging of cavities or the overflowing of eaves into cavity walls. Generally the concrete slab itself with the plastic membrane under neath is a good water proofer in itself thus negating any moisture conning up from under the slab.

If all these basic building rules have not been broken and the damp still persists (highly unlikely) then other more effective chemical means may have to be implemented. These include the chemical injection of silicone liquids under pressure this is usually done by competent trades specialising in this type of work. Another method that I have heard and read about is the “FREEZTEQ” damp course System that can be done by the handyman or women.

We want you the reader to write to us on any building matters, questions or if you seek advise, we will gladly answer any topic that you wish us to discuss.

Improving Subfloor Ventilation

Subfloor Ventilation

We will look at improving sub-floor ventilation which if not done correctly can be a cause of decay to timber components.

The other day we were asked to inspect an older style home in Nedlands it was a grand old mansion with timber flooring through out, massive ceilings space and it was oozing with old world charm. Generally the home was in good shape some of the roof timber were showings signs of sag and ageing but one room in particular was extremely cold, and it almost reminded me of the spooky stories one reads about cold rooms in haunted homes, but no such luck.
It turned out, after removing the inspection (male/female) opening in between the floor joists, it was obvious why the room was so cold.

CSIRO (Commonwealth Scientific and Industrial Research Organisation)

For starters the distance between the ground and the floor was very close, the home was on a sloped block, and sub-floor ventilation was minimal. I will insert some data facts as supplied by CSIRO to us, on how to improve the subfloor ventilation with some interesting and commonsense applications, but you may well ask what has a sloping block to do with it. Well when water via rain is deposited around the perimeter of a house if the home sits on a flat block of land the water will seep into the ground vertically down. If the block is sloped the water that may pond in areas can and will flow down the hill and seep into the ground as it progresses down the incline of the land and hence we get damp and moisture under areas that would mot normally get damp on a level block.

Now the CSIRO Division receives an steady stream of requests for advise on prevention and correction of decay in flooring and in the majority of cases the problem is one of inadequate subfloor ventilation, that is for a free flow of air under all parts of suspended timber floors.

Older Building

In older buildings the problem can be complicated by an ineffective dam-proof course, by leakages from water supplies or wastes or by the discharge of storm water into the sub-floor cavity, further more in older buildings the provisions for under-floor ventilation is often inadequate.

We shall take a case in point, where in a double brick dwelling circa(1920) most of the timber flooring had to be renewed. During the repairs the size and numbers of openings in the brickwork below floor level was increased because, with a few exceptions, the only provisions originally provided for ventilation was the openings in the brick work beneath the doorways. Before the new flooring was laid, extra openings were provided within one(1) to two(2) meters of every corner of every room and midway along any wall over five(5) meters long. Each of the new openings occupied the space of at least two bricks.

In addition because of the low sub-floor clearance and the difficulty of providing good cross ventilation, plastic sheeting was spread out over the ground and under all new flooring so as to reduce the area from which soil moisture could evaporate into the sub-floor cavity. Mortar droppings and other debris were removed from the inside of all external ventilator openings and finally the ventilators themselves were replaced.

Replacement of the ventilators was an essential part of the repairs.

Surprisingly the smaller of the original terracotta vents provided for rather more free airway than the double brick size, even though the latter had one more opening. However in practice, nether allowed for much air exchange between the subfloor space and the outside because the openings had been blocked by spiders and assorted debris. The pressed metal vents that were used to replace the original terra-cotta air bricks allow for about ten(10) times as much air flow through each opening. This together with the other measures taken should ensure that conditions conducive to decay do not develop again under that floor.

Adequate subfloor ventilation

Adequate subfloor ventilation is also an essential requirement which is often overlooked when remedying the problem of excessive dampness in walls, by effectively ventilating all subfloor cavities, moisture that evaporates from the soil or the foundation is removed and the sub-floor humidity is prevented from rising. However achieving an airflow across or along the sub-floor space can be difficult in some houses, especially in terraces where there can be problems in providing vents at both ends of the house.

In case like that the Division often recommends the utilisation of disused fireplaces as a means of venting. If decorative facing is placed over the front of a fireplace openings cut through the hearth to the sub-floor space and a cowling or chimney pot placed on top of the chimney then a n up-draught will be created when the wind blows over the roof and air will be drawn from under the floor.

Any questions that our readers may have would be gladly welcomed and endeavoured to be answered as seen fit.

What causes condensation in houses?

What Causes condensation?

THE AIR AROUND US ALWAYS Contains A CERTAIN AMOUNT OF WATER VAPOUR BUT THE AMOUNT THAT CAN BE PRESENT AT ANY TIME DEPENDS ON THE TEMPERATURE OF THE AIR.

When moist air is cooled below its “dew” point that is (cooled to temperature at which it cannot contain all the water originally present) and if the cooling is caused by contact with a colder surface, then the surplus water appears as droplets on that surface, we call this condensation.

In real every day analogy it translate like this:- we hardly notice the air around us on an average day, then night time approaches, the temperature drops, and things become cold as the temperature drops, so does the air, if this dropping in temperature continues then the water vapour that occurs naturally in the air turns into water and if cold enough into ice.

Air in a house can become moister because the occupants and some appliances produce water vapor. Typical quantities of water vapor produced in a home are:-

  • Adults breathing 0.1 liters/hr
  • Hot Bath 1.5 liters/hr
  • Washing Machine 3.0 liters/hr
  • Clothes Drier 5.0 liters/hr
  • Hot Shower 10.0 liters/hr

Water vapor is also generated in large quantities by gas stoves/hot plates and kerosene heaters so much so that a lot of water may be stored in the air each day as water vapour.

On cold days much of this water will condense (if the ventilation rate is low) on cold window panes and even on walls. Little wonder then when some house holders complain of mold, decay and damp carpets.

Steam coming from service areas such as kitchens laundries and bathrooms travel to other rooms in the house, even if these rooms are a considerable distance away. The worst condensation problems generally occur in unheated rooms facing south which receive little heat from the sun. The movement of the water vapour within the air (using the air as a travel medium) travelling from service areas to other rooms such as bedrooms is due to the difference in water vapour pressure.

Condensation in new homes

Severe condensation problems often occur in new homes as construction moisture is stored in the bricks floor etc. in addition to the moisture generated by the occupants. It will take about six to 12 months for the water to evaporate. Some of this moisture will be lost to the outside air by natural ventilation and much will find its way into other rooms in the house.

If moist air from the rooms is exhausted into the roof space, sever condensation may occur within the roof space causing costly damage to ceilings, roof members and insulation materials.

  • Poorly vented pitched tiled roofs with aluminium foil sarking directly beneath the tiles. To reduce the risk of condensation, ventilation should be provided in the eaves and gable ends.
  • Flat metal deck or cathedral roofs. On no account should moist air be exhausted into these roof spaces. It should be carried by flues passing right through the roof space (or external walls) to the outside air. Sever condensation could also occur if such roof spaces were connected via wall cavities to a moist sub-floor space.

Technical information by courtesy of CSIRO.
For now till next week when we will discuss
“HOW TO STOP CONDENSATION IN HOUSES”
your “Handy Jock”.

Any questions that our readers may have would be gladly welcomed and endeavored to be answered as seen fit.

How to stop condensation in Houses?

Continued from the post > Condensation Issues

Condensation is basically simple. It involves preventing moist air from coming into contact with cold surfaces (ie. surfaces at temperatures below the dew point of air). In practice this can be achieved by:

  • Removing moisture laden air (by ventilation) and/or
  • Raising the temperature of any cold interior surface to a level above the room air dew point (by heating).

The best way to remove moist air is to use exhaust fans as its source. An electric fan should be installed in the ceilings of the bathrooms and switched on when using showers or baths. To enable the fan to work more effectively, leave a door or window slightly open while the fan is running.

A ceiling vent is recommended over every sink, basin or trough in the house.

More water vapour is normally generated in laundries tan in any other room. Clothes driers should be ducted to the outside air.

A hood fitted with an exhaust fan is recommended over hot plates and stoves as follows:

  • The exhaust fan should be at least 200 mm in diameter.
  • The distance between the hotplate and hood should be 600 mm, this distance may be increased to 750 mm if absolutely necessary.
  • The width and depth of the hood should be preferably the same as the hot plate or stove.

If it is not practical to install a hood, an exhaust fan may be located in the ceiling over the stove and used while cooking.

In rooms where exhaust fans are impracticable (eg. bedrooms) adequate ventilation can be obtained by opening windows.

Remember it is better to ventilate continuously by having all windows slightly open than by opening one window wide for a short time.

Heating

In addition to good ventilation, heating can also help to reduce condensation on walls and ceilings. Condensation on window panes and metal window frames, however, is not significantly reduced by heating. This is because glass and metal are good conductors of heat. Any heat which reaches these surfaces does not warm them appreciably as the heat quickly is lost to the outside air.

In very cold climates (and in Australia this can be takes to mean in areas above the snow line), it may be necessary to provide double glazing to raise the temperature of the inner pane.

It is better to provide some continuous background heating rather than short burst of heating. Continuous heating allows wall and ceiling surfaces to warm up and stay warm, which greatly reduces the risk of condensation. On cold days try to keep inside air temperatures at least 5oC higher than outside air temperatures.

Insulation

The risk of condensation is considerably reduce in any room if walls and ceiling are insulated, because it allows these surfaces to reach a higher temperature. For an existing house it may not be practical to insulate walls, but ceilings can usually be easily insulated. Apart from reducing the risk of condensation and mould growth, insulation will substantially reduce heating costs.

Technical information by Courtesy of CSIRO.

Your “Handy Jock”.

Any questions that our readers may have would be gladly welcomed and endeavoured to be answered as seen fit.

Best Wall Coverings practices

Vinyl wall coverings (vinyl laminated to paper or fabric) have become very popular over the last few years, largely because they are more easily cleaned than the uncoated open-textured types. Yet it is just this impervious, otherwise-desirable surface that sometimes creates a mould problem.

In one home examined by the Division of CSIRO, red and purple stains were found to be showing through from behind a light coloured vinyl wall covering within two weeks of application. The stains, which originated in the paste layer, were identified as a type of mould. The key factor in this rapid mould growth was the fact that paste had been sandwiched between a painted wall and a sub-substantial vinyl membrane.

On one hand, the impervious vinyl layer prevented evaporation of moisture from the paste layer while on the other hand, the painted background drastically reduced absorption of water into the wall. Thus, the paste was kept moist long enough for mould growth to start. Had an adhesive offering less nourishment to moulds been used, mould growth would have been unlikely. Similarly, had the wall covering been a plain paper or one of the “spongeable” wallpapers (papers with a very thin plastic film on the surface), or one of the “breathable” vinyls, mould growth would again have been unlikely since such coverings “breathe”, enabling the paste to dry by evaporation.

When hanging wall coverings of solid vinyl sheet laminated to paper, it is a wise precaution to apply a fungicidal wash such as two percent sodium hypochlorite solution to the wall before sizing it with a dilute solution of a cellulose adhesive with fungicide added. For best results manufacturers suggest applying lining paper to the wall before finally hanging the wall covering, using the heavy-duty cellulose adhesive for both operations. In the case of mould staining described above the vinyl wall overing had been hung, without a preliminary fungicidal ash, using a starch paste (instead of a cellulose adhesive) with fungicide added. Obviously this was not enough protection.

When the weather is very cold and damp the cellulose adhesive may take a long time to set, so an acrylic-reinforced latex adhesive might be advisable under such conditions, to avoid lifting of the seams. Alternatively, he cellulose adhesive could be used and, if the seams do lift, they could be bonded to the wall with the latex. When hanging wall coverings of vinyl sheet laminated to fabric, only the specially formulated adhesives recommended by the manufacturers should be used.

Normally, coverings are not hung on absorbent surfaces. Manufacturers recommend that bare surfaces be painted with a flat oil paint, and it has been assumed in the above that this has been done.

For now till next week when we will discuss

“RAIN PENETRATION OF SOLID MASONARY WALLS”
your “Handy Jock”.

Any questions that our readers may have would be gladly welcomed and endeavoured to be answered as seen fit.

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