New build house - air bricks placed incorrectly?

stuart45

He said it was a suspended block and beam concrete floor.

pinkcloud17

tonyh66 said:

Seeing you haven't had a proper answer yet,(Stuart45 was closest) the airbricks are there to provide air flow into your underfloor void. This stops the floor timbers from rotting and prevents condensation. The floor timbers sit on the internal wall and dwarf walls all above DPC level (generally 2 bricks above ground). What you have is that the gardeners have put the topsoil and turf down and ignored the level of the DPC covering the airbricks (they are in the right place BTW). You need to get onto the developers and tell them that their landscapers have bridged the DPC (assuming you paid the developers to do the garden) the level of the garden at the wall needs to come down.

Personally I wouldn't have turf right up to the edge of the house, a small gravelled area can be beneficial to drain excess water.

Having reread your OP your floor is concrete beam and block, the airbricks still should be open, from the photos you posted (now gone..) the garden is definitely bridging DPC.

Thank you for your reply. Would there still be an underfloor void if the floor is concrete and if so would it not be bad to have air bricks because it could let air and moisture in to the cavity walls? I think I have cavity walls any way.

Now the neighbours fencing has been removed and I can walk up to the door, it appears I have been jumping to conclusions. From afar it looked very much like the turf was right up to the edge of the house but it actually looks like this photo. 

I'm not as concerned now but I dont know what drainage is in place and still a little worrying that the turf slopes towards the house and the air bricks. 

Also not happy about the retaining wall between me and my neighbour because their garden is exactly level with it. If their garden became waterlogged, water could start spilling into mine above the DPC. Would you recommend asking for the wall to be raised? 

Not entirely sure if my DPC meets standards in terms of its height above ground level or how I would measure that.

Thank you.

stuart45

The airbricks should have liners that take the air through into the void and won't allow it into the cavity. The cavity should have a small amount of ventilation with weep vents.

TELLIT01

Airbricks will have been installed for a reason, and they should not be covered.  The OP needs to speak to the developer and get the problem sorted before it starts to cause problems.

weeg

I don't see you saying anywhere that the floor is beam and block? If it is then that's very unusual for a mass housebuilder in Scotland. It's certainly not the Barratt standard design (I say this with the absolute certainty of a person who has access to their standard house type drawings). Their standard is insitu slabs designed as suspended. As are pretty much all their competitors.
I'd also not worry overmuch about runoff from grass. The site, including the slopes and substructure drainage will have been designed to ensure this doesn't happen except in exceptional circumstances. (which is a 1 per 100 year storm, with an allowance for increased rain from climate change). Most of Scotland has a glacial till soil, which drains much faster that the soils you get down south. 

RelievedSheff

weeg said:

I don't see you saying anywhere that the floor is beam and block? If it is then that's very unusual for a mass housebuilder in Scotland. It's certainly not the Barratt standard design (I say this with the absolute certainty of a person who has access to their standard house type drawings). Their standard is insitu slabs designed as suspended. As are pretty much all their competitors.
I'd also not worry overmuch about runoff from grass. The site, including the slopes and substructure drainage will have been designed to ensure this doesn't happen except in exceptional circumstances. (which is a 1 per 100 year storm, with an allowance for increased rain from climate change). Most of Scotland has a glacial till soil, which drains much faster that the soils you get down south. 

Insitu concrete slabs can not be used in all situations. There is no such thing as a "standard" floor construction as each site differs so wildly.

Examples of where suspended slabs have to be used are for gas protection measures or where trees are within influencing distance of the plot in which case a ventilated void is required to allow room for the ground beneath to heave.

weeg

RelievedSheff said:

weeg said:

I don't see you saying anywhere that the floor is beam and block? If it is then that's very unusual for a mass housebuilder in Scotland. It's certainly not the Barratt standard design (I say this with the absolute certainty of a person who has access to their standard house type drawings). Their standard is insitu slabs designed as suspended. As are pretty much all their competitors.
I'd also not worry overmuch about runoff from grass. The site, including the slopes and substructure drainage will have been designed to ensure this doesn't happen except in exceptional circumstances. (which is a 1 per 100 year storm, with an allowance for increased rain from climate change). Most of Scotland has a glacial till soil, which drains much faster that the soils you get down south. 

Insitu concrete slabs can not be used in all situations. There is no such thing as a "standard" floor construction as each site differs so wildly.

Examples of where suspended slabs have to be used are for gas protection measures or where trees are within influencing distance of the plot in which case a ventilated void is required to allow room for the ground beneath to heave.

No offence, but there very much is a thing a standard construction across the central belt, down in to the borders and up in to Perthshire. We put gas protection measures under slabs on solid - the solid in question being single sized stone to allow airflow, with membranes under the slab.

New build sites with listed trees are uncommon (although they do exist). But the geology in this part of the country has high rock heads, with glacial till, for the most part. Soil heave is an issue in places with deep clay layers - the London region is bad for it. It isn't something I've ever had an issue with in Scotland.

This is literally my dayjob. 

OP - sorry for the threadjack. 

stuart45

I think the terminology must be different in England to Scotland as well as the Regs. 
A concrete ground floor slab built insitu with no void here is called a ground bearing slab. A suspended concrete ground floor would be block and beam. Can't remember on any houses in England where the ground floor insitu slab sat on the inner skin. I've seen it on upper floors on flats and commercials where a reinforced concrete slab was used. 

molerat

I am assuming timber frame judging by the set back of the windows so a suspended concrete floor would be quite unusual.

weeg

stuart45 said:

I think the terminology must be different in England to Scotland as well as the Regs. 
A concrete ground floor slab built insitu with no void here is called a ground bearing slab. A suspended concrete ground floor would be block and beam. Can't remember on any houses in England where the ground floor insitu slab sat on the inner skin. I've seen it on upper floors on flats and commercials where a reinforced concrete slab was used. 

In engineering terms, it's suspended if it is supported on the foundations, like this one (grabbed at random). Even if it does sit on the ground. (NHBC standards insist on a slab being designed as suspended if there is more than 600mm upfill, in practice this means slabs are always designed as spanning, as it's easier/ less variation. Same standards throughout the UK)

I'm going to get over myself now and butt out.