Extending air bricks under conservatory base.

[Black Shuck]

Hi, I am wondering if someone here can advise.

I am preparing a conservatory base, and I need to extend the airbricks on the back of my house, out to the new front edge of my conserveatory dwarf wall. What would people use to connect up the old brick to the new, before filling the lot with concrete?

My local Travis Perkins said there is a connector that fits on the back of the air brick, and allows you to "pipe" to the old one. They did not sell them, and did not know anyone that did. He did have some box section stuff, at insane prices, that according to him, nobody bought because of the price...

So what do people generally use?

Thanks in advance.

[al]

brickwork and ignore the existing one? Al

[Andrew Mawson]

airbricks on

because of

I built my attached garage I piped four airbricks to the outside using standard 110mm underground soil pipe. Removed old airbrick (9" x

9" galvanised cast iron), mortared the pipe into the hole, and lead it to the outer skin of the dwarf walls up against the new airbricks which I again sealed with mortar. Then the slab was poured holding it all together. The BCO was very happy with the method.

AWEM

[Cicero]

=================================== You might be able to use these (Telescopic underfloor vents) but they would open into your conservatory and the air flow would be from inside the conservatory into the old flooring void:

?_dyncharset=UTF-8&fh_search=underfloor+air+vents&x=0&y=0If you used them they would have the possible advantage of being easier to keep clear than long underground pipes.

Cic.

[Chris George]

My advice is to get rid of the existing air BRICKS (80% material 20% air) and put in your hardcore 150mm if you can get it or 2 x 110 mm if you cannot piping from each postion (normally 225 x 150) of each brick try to keep the pipes as straight as possible before they then get turned up to the vertical where indeed you could use a telescopic vent as shown by Cicero (nice choice of name) or simply two 90 deg bends to the new positions on the rear wall of the conservatory. AT this point use purpose made sub-floor air VENTS (80% void 20%material) AND consider insect mesh. The higher up the wall the vent goes the more force of air (wind pressure) down the pipes. Presumably it is cavity wall so ensure the cavity is large enough at these points if you do not use the telescopic connectors Chris

[Weatherlawyer]

Boy! That's a long sentence. Have you taught yourself to speak as you inhale?

Could you repeat that? I forgot what you said.

I can't see the need for airbrick on a building with a concrete slab but if I was going to do it, I would suggest that the air intake be higher than the lowest sewer input in the house.

If that is possible, it will save you putting covers over them if you are in danger of flood. Anything higher will be a waste of effort as ingress from foul water is much worse than the alternative.

I wonder if blocking the doors from the inside and turning on the down stair taps would be a preferable alternative to either other choice of floodwater ingress. Any ideas, anyone?

[Chris George]

Dear Weatherlawyer re I can't see the need for airbrick on a building with a concrete slab but if I was going to do it, I would suggest that the air intake be higher than the lowest sewer input in the house.

One of the major reasons for Wet Rot decay in the rear wallplate and joist ends of a suspended timber floor to which some idiot has chosen to put a concrete floored extension is the failure to produce adequate facility to maintain or increase subfloor ventilation to the existing floors. Where there is a capacity to do this from the sides (detached houses) fine but with a terraced house, the way I have suggested is best. If the property is subject to flooding, other considerations apply and suppose it were intermittent infrequent but regular flooding of the oversite but not the floor then the obvious solution would be to continue in suspended timber with land drains on the mandatory 4" of concrete on the new oversite. Old oversite would naturally drain if of earth. If, however, it was more serious flooding the issues are far too complex to be solved by anything done or not done with subfloor ventilation. It is another topic!

Air vents need to be a min 150mm above external ground level at the base.

Chris