Missing air brick after extension?

[Julb]

Hi all,

I’m currently house hunting, and I’ve done a viewing of a Mid terrace Victorian property which looked almost perfect, so I’m considering making an offer

only thing bothering me is that it might have a subfloor ventilation issue. Living room is on suspended floor, I couldn’t see any issue, didn’t seem bouncy.

At the front, I noticed one of the air brick was removed, leaving a gap. Not sure why and that seemed suspicious. I asked the estate agent to explain why it wasn’t there but he didn’t know either.

At the back, the kitchen has been extended, the floor in the extensio is a concrete slab. The issue is I couldn’t see any air brick at the back of extension. There’s a drainage channel between patio and back wall, so could it be that air bricks are below that (seems unlikely though) ? If not that means no cross ventilation. I asked estate agents again and he didn’t know, and is going to try and find out.

Could it be that some other way not using airbricks is used to ventilate the suspended subfloor?

I’ll obviously wait for the EA to come back, but what do you guys think?

Thanks !

 

[JohnD]

At the front, I noticed one of the air brick was removed, leaving a gap. Not sure why and that seemed suspicious.

are you sure there used to be an airbrick? maybe they just took out an ordinary brick, to add ventilation.

Were you able to see other airbricks? It is quite common for numbskulls to block airbricks by raising the height of paving above the original DPC, in order to create damp and rot.

yes it is quite possible that the "drainage channel" is an attempt to un-bridge the original DPC, and the old airbricks might be under or inside it. have they filled this channel with stones or gravel? Maybe the numbskulls forgot to put in drains for the gutter downpipes or the kitchen sink and left a trough for the water to run alongside the house.

It is also quite common for numbskulls to block airbricks by adding extensions, with concrete floors, encasing the original external wall.

It is possible to rectify these errors, but it is a lot more cost and effort than avoiding them in the first place, and very annoying.

If you go back, find the original DPC and photograph it, and the original airbricks, and photograph them

The only good reason for taking out an (air)brick and leaving a gap, is if you are fond of rats and mice and want to offer them a home under your floor.

 

[Julb]

Hi , good point about the missing brick not being an airbrick in the first place, this is a possibility. I was able to see one other air brick at the front.

About the drain channel, might have been some gravel at the bottom, but couldn’t see too much because of the metal grating (couldn’t spot an air brick but might just have missed it).

I will go back next weekend and
try to get the pictures suggested.

assuming they blocked the original walls with concrete without care for the subfloor ventilation, do you know how much would be the cost of fixing that be? (Very rough estimate)
This is a 4 meter extension.


thanks a lot!

 

[Mottie]

assuming they blocked the original walls with concrete without care for the subfloor ventilation, do you know how much would be the cost of fixing that be? (Very rough estimate)
This is a 4 meter extension.

When we had a little front extension with a concrete floor, the air vents were extended in the floor with tubes. If you have to do that to your 4 metre extension, I would imagine it would be a fair sized job to hammer it all up to extend the air vents. No idea on the price but I’d imagine it would be into the thousands.

 

[JohnD]

It is possible to rectify these errors, but it is a lot more cost and effort than avoiding them in the first place, and very annoying.

grrrrrr.

 

[SpecialK]

Building control normally insist on extending the underfloor ventilation.
Perhaps the extension was not built to current regs? Do you know when it was completed?