Air Bricks Below Damp Course

[DarceyK123]

Friend is looking to buy a house, the survey has come back as the damp course & air bricks have had a patio built over it so may cause damp although there doesnt appear to be any now.

Is this a big problem? Expensive to fix?

Thanks for any advice,

[Ryzen]

The patio could be cut back around 300mm from the house to allow circulation.However if obvious botches are evident I would have the property inspected for any hidden ones.

[Togo]

I would be wary. If the damp course is bridged it can cause damp problems that are themselves dependant on a number of conditions. ie. prevailing wind and rain, whether a cavity insulation is fitted, is it a sunny elevation? etc, etc. The air bricks being covered "could" lead to problems with the under floor structure that I assume is timber joists. They could be susceptible to damp rot or moisture retention which in itself can lead to the deadly dry rot. I would get a further survey by an independent surveyor before committing, if I fancied the property otherwise. Perhaps Builder will spot your post, he is probably the best of us to give this sort of advice.

[The Builder]

Easy to say now, but any airbrick should have had a simple plastic duct placed in front of it, so that air is taken from the other end of the patio. The pipe would run all the way under the patio.

If (and it's not likely) you can figure out where the hidden vents are, then take up a slab (the one covering the vent), and fit one of these..................

https://www.toolstation.com/9-x-3-telescopic-vent/p38967?store=EX&utm_source=googleshopping&utm_medium=feed&;utm_campaign=googleshoppingfeed&gclid=CjwKCAjwgqbpBRAREiwAF046JUO1x9iQ01r9NGrmWOMz5r4dt1cw_gSokkLhy0VVaFlOOqZusmrZixoCrJwQAvD_BwE

I suppose you could lift the row of slabs nearest the house until you find the vent(s), then fit the telescopic vent where needed.

I assume you have a suspended timber floor. Without crossflow air, it's the timbers that are at risk. There should be very little risk of damp in the walls.

Perhaps look to each side of the patio and drill some new vents into the house wall. simple, inexpensive job. The vents do'n necessarily need to be exactly in the right position as long as there are enough of them. Any decent builder will advise.

[DarceyK123]

Thanks guys, its difficult as they are only thinking of buying the place so cant really go around drilling or lifting anything.

I assume this can all be rectified, but at what cost?

[Old_Geezer]

No expert but I'd have thought not too expensive to chip/cut the patio away from near the house. Maybe an idea to ask the surveyor whether they had an off the record opinion on whether it has caused damage and what to look further into ?