Underfloor Ventilation

[staningrimsby]

Hi Guys,

Sonn going to start building on the kitchen extesion, the new extension will have a concrete floor as fiollows;

1. 150mm of brick hardcore
2. 50mm blinding Sand
3. 1200 gauge DPM
4. 75mm Kingspan
5. 500 Gauge polythene
6. 100mm Concrete
7. 50mm Screed.

My problem is that this extesion will connect to the dining room and the kitchen, were the dining room has a wooden floor. So how do i go about ventilation for the dining room floor.

As the current air bricks will be blocked by the new extension ???

 

[dude_diy]

could always add in a few air bricks either side of the new extension walls if possible? but I dont actually think you will need them because it links up with a new extension and will now be an internal not external if that makes sense. Im sure others on hear will be able to comment further. Cheers.

 

[^woody^]

You need to maintain through ventilation, so avoid putting airbiricks in a side elevation wall - this can lead to unventilated corners.

You need to duct the air from the new external wall under the concrete and for this you would use either 1 section of 100mm underground drain pipe or 2 x 70mm downpipes per airbrick.

You may also need to use telescopic liners (aka persiscopes) in the cavity wall to get the pipe below the floor slab

 

[staningrimsby]

Yep i know exactly what you mean thanx Woody, do the periscopes extend a decent length because im presuming that the 100mm pipe will go in at hard core level, is that right ???

 

[^woody^]

Yes they normally go down enough - you can see them on the Screwfix site

 

[staningrimsby]

Cheers Woody I have seen them before in the screwfix book but was just a bit unsure as to wether it would go down the cavity far enough.