WELCOME TO OUR DAMP OR MOULD PROJECT
This project is presented by Property Repair Systems
Summary: Damp or mould growth on the inside of external walls
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If you need any help with any type of Damp or Mould or timber repair, maintenance and damp problems, Property Repair Systems will be pleased to give you completely free, no obligation advice on 01626 331351. The information you need may be in the project below, if not, call them.
Get to the cause of the problem; deal only with the effect afterwards….A very deep cut will still bleed no matter how many plasters you apply…A stitch in time…………………..
Many, many customers ask us for advice when they have damp spots on the inside of external walls. Most think they have rising damp. This is generally not the case and there are many reasons for damp within a building, and all of the following should be checked before embarking on the major project of DPC injection or tanking. Unless evaporation is totally prevented from the walls, it is impossible for rising damp to affect a wall above 1.20m (4 feet). Gravity will pull the water down before it reaches this height. Our specialist projects on rising damp and ways of dealing with it will give you a greater degree of protection should this prove to be the problem.
Do not attempt to decorate by sealing these damp spots in the wall…Moisture must be allowed to evaporate and the cause of the damp must be found. Sealing moisture in will lead to larger, more expensive problems. Damp will sometimes remove the adhesion between plaster and wall, leaving the area “hollow”. It is better to remove and re-plaster this section. Plasterboard will swell and lose its insulative /decorative qualities. This is also better replaced. Mould can be treated by many fungicidal solutions on the market today and fungicidal protective paints are available for areas of high humidity. Kitchen and bathroom paints are generally oil-based eggshell, which will not allow the absorption of water.To decorate over an area that has been water stained, a coat of oil based paint or stain block will need to be applied first. If not, a stain will bleed through no matter how many coats of emulsion you apply.
Remember buildings must breathe. There is a natural water content in all building materials. If this is sealed in by a waterproof coat on the outside and similar applications on the inside no evapouration can occur and the water will be trapped. This will lead to rot which in turn will cause damage and health risks.
Check for a damp proof course. If you do not have one at all, think seriously about getting one installed. We have installers and damp specialists in our “locate a specialist” directories. and much more information can be gleaned from our rising damp and damp proofing projects.
If the damp is at floor level, check for evidence of old doorways being bricked up without a dpc inserted.
Check every bit of masonry for defective mortar joints, or if the walls are rendered, look for cracks. With older stonework, look for cracked and broken stones.
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Is your patio too high or running towards the property?
Look for white, salty deposits on the brickwork etc. This is called efflorescence, and is a sure sign that there is an excess of moisture within the structure. When the moisture evaporates from the wall, it leaves behind the salts it has extracted from the masonry and or mortar. How is it getting in?
Check above and around windows/doors for a bad seal, water can get in and trickle through joints to find a weak spot.
Check all ground levels, paths etc close to the house, are they at least 6 inches below the damp proof course? If they are not, dig them back. If this is impossible, go to our project on French drains
Check roof tiles for damage. Water can get in and run down the roofing felt, collect in the bottom of the felt where it meets the external walls and rot through. This will allow water onto the top of the walls; this can then trickle down through masonry joints and come in through a weak spot. Advice on this can be sought from the diydoctor forum.
Check all gutters for leakage, blockages and overflow. A constantly damp wall will suck moisture in.
Check your overflow pipes for the same reason.
Check any abutments to the wall and the joint it creates.
Check for holes made in walls for hanging baskets etc.
Get your drains checked for broken or blocked pipes and manholes.
Check all lead flashings for correct sealing at the point where they are chased into the wall and correct coverage to the surface and joint they are protecting.
Check outside taps for leaks.
Outside flues can sometimes cause condensation on the external wall they rise on, check the masonry in this area. (Make sure the boiler is off for this check).
Once you are absolutely sure the moisture is not getting in from the outside, check all internal pipe and waste connections to washing machines, sinks, basins, dishwashers etc. Check all downstairs (and upstairs) toilet wastes and cistern connections and look for condensation on the cold feed pipes to all taps and valves. Then if you are sure these are not the cause either, read our article on condensation
The damp meters to the side and below can be used to detect damp and the plugging chisel below is a very useful tool for removing brickwork joints to repoint damaged areas. Plastic DPC can be bought in our toolstore and when using cement mortar out of buckets a bucket trowel is invaluable. Small, largely unseen
areas of render can be painted with waterproof "Bitumen" paint below, while small cracks can be filled using sealant and an applicator gun. All of these items are available below and to the side. Information for all of the above can be found on the Property Repair Systems website.
Take a look at our video sections on "damp or mould" and "removing mould" for various videos that give advice and tips for tackling this common problem.
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Much more construction information is available in our bookstore. All the tools and fittings you need in the toolstore.
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