New Houses don't have air bricks

[MoonMan2]

Noticed that a whole lot of new builds in my area don't have the standard air bricks you would expect on houses.

They have these small "weep holes" all around the house.

Untitled

• MoonMan2
• 24 Aug 2010
• 3

Assuming the houses have a cavity (ie two layers of brick), how can the sub floor solum be getting proper ventilation - even with the weep holes surely the amount of fresh air in the cavity would be minimal.

If someone knows the reason for this (links to diagrams would be great) and would be happy to spare 10 minutes of their time typing in an explanation, I would appreciate it.

 

[RedHerring2]

Solid floors?

 

[stuart45]

If they are around DPC level, it's probably a timber framed house.
They are put in as a dual purpose to drain and vent the cavity. Sometimes put in on a normal cavity wall.

 

[Hugh Jaleak]

Others more knowlegeable may correct me, but most new builds now have either a solid concrete ground floor or 'beam and block' floors. Solid floors have a hardcore sub base, then a membrane is laid to prevent damp, onto which concrete is poured and levelled. Screed is laid to provide finished floor surface. Beam and block, concrete beams are laid, blocks used to fill the gaps and then the whole lot is screeded over.

Older properties with suspended wooden floors require ventilation to prevent dry rot taking hold. A solid concrete floor doesnt have a void underneath, beam and block is concrete so damp is not an issue.

 

[RedHerring2]

I think, not sure, that beam & block floors should also be vented but not necessarily to the same degree or for the same reason.

 

[stuart45]

I think, not sure, that beam & block floors should also be vented but not necessarily to the same degree or for the same reason.

You are correct. If there's a gas leak under the floor, or gases building up from waste in the ground or condensation forming on the bottom and going up.

 

[^woody^]

Those weep hole are not venting, they are draining the cavity - there must be a cavity tray on that course, or if they are below the DPC then that is the level of the concrete fill in the cavity. Normally a weep hole every 900mm (4 bricks)