How Much Does It Cost To Cure/Treat Penetrating Damp?



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Cost to Cure/Treat Penetrating Damp






Job
Description
Labour
1 Re-pointing is covered in its own article.

2 Re sealing around widows is an easy job and doesn’t need scaffolding. Only good quality silicone should be used and all the old stuff must be removed first. To re seal one window will take half an hour. The more you do the cheaper it gets. All your windows can easily be done in a day and this includes 2/3 tubes of expensive silicone at £8 a tube.
£200
3 One man can give a complete gable end two coats of water seal from ladders in a leisurely morning. Spray gun hire will cost £20. The best quality sealant costs £30 for 5 litres and one tin will be enough. So including materials…
£140

“Labour” at £175 a day (tradesman) £100 (labourer), includes incidental fixings etc. and tipping charges. “Materials” if mentioned, are larger things (a boiler) and stuff only you can choose (tiles etc).  Also VAT must be added all round

Information Sheet on Penetrating Damp


Assuming we can remove both roof and loft pipe leaks from this particular equation, penetrating damp for the benefit of this article is rain water that passes horizontally (or more likely diagonally) through the external walls of the house, as opposed to it’s equally annoying cousin rising damp, which rises up through the walls from the ground.

Penetrating damp occurs at all levels of the building but is more prevalent higher up and on south west facing walls.

THE CAUSES…

Poor pointing
When a house is built, very often the brickie doesn’t finish off the visible edge of the mortar which surrounds each brick until some time after he has constructed the wall. This is because it takes time to make these edges look pretty so he waits till the end and does it all at the same time. This was far more relevant in Victorian times when they took time creating different pointing styles as opposed to nowadays, when they finish it as they go with an old bucket handle (its true)!

Unfortunately, this means that “pointing” in older houses is not integral with the bricklaying mortar and after 50 years or so, wind and water action can wear it away. This leaves ledges at the top of each brick, which gives water a chance to start penetrating.

If the wall is solid (with no cavity), which Victorian and 1920’s houses are, prolonged rain on exposed walls can mean that this water finds a way to the inside. Even if the wall is of cavity construction, if it was badly constructed (by Jerry and his friends possibly) the cavity can be bridged and water still passes through.

Porous Brickwork
Bricks are porous, some are a lot more porous than others. Yes…you guessed it, Victorian ones are the worst. It depends on the clay used and how they were made.


Older ones are often hand made and full of tiny holes, those from the 30’s are as solid as United’s defence. Also and I have no idea why it happens but I have discovered areas of brickwork in Victorian houses with no pointing problems, that are not even particularly exposed, have never previously been affected, that suddenly start to let water in.

Around Openings
Window frames often let water past them into the room. Victorian (Oh… give them a break) window cills are a nightmare. I‘ve lost count of the number of these houses I’ve seen with damp walls under the windows. It’s no coincidence that that’s where the radiator is always found! Doors, extractor fans and boiler flues are also ingress routes. The leakage is caused as (wooden or PVCu) window and door frames expand and contract at different rates to the surrounding brickwork. This leaves a crack and what does water like?

THE CURES…

Repoint the wall
The main problem with this is when not all the wall needs doing. Pointing just a bit, will show up horribly against the older stuff that’s still ok. You have to make a decision but there is a full section on pointing if you care to take a wee look!

Reseal the window and door openings
When this is undertaken make sure all the original stuff is completely removed and good quality silicone is used. This sticks better and expands more than the cheaper stuff.

Washing the Wall
With a proprietary water sealer. This soaks into the first few millimetres of brickwork fills up all the miniscule holes, then sets and prevents subsequent water ingress. It’s cheap stuff so have at least three coats put on. He can hire a spray gun that he wears on his back and he’ll look just like a cyberman.

Unfortunately water sealer doesn’t seal cracks, so these must be repointed. They can be filled with clear silicone from a tube but it will show. If you decide to do this, have the bloke scrape out and enlarge the crack first, this will leave a larger (crack) surface for the stuff to stick to and just maybe he won’t feel the need to smear it all over the adjacent wall as well.


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