How to Get a Block and Brick House Air Tight? - Part 1 - ATSPACE

Hi, it's Paul Whiffin from ATSPACE
we get quite a lot of enquires asking
how permeable the walls are, the blockwork walls
and the floors so, we thought it would be a great idea to get to a site
with a blower door and a smoke machine and what we will be doing is
we'll be emitting a load of smoke into the room and use the blower door to pressurise this room to force the smoke through the blockwork and the floor to see what happens and then we'll go outside to take a quick look to see what's happeningWaahooo!

Right ok, so, we are outside the building now
we've got the fan on full blast we're getting about 100 pascals of pressure
we filled the place up with smoke and as you can see we are pushing smoke through the inner leaf of the blockwork into the cavity and onto the outer leaf so, you can see quite clearly, we are getting a lot of smoke
all the bedding sort of joints are poorly pointed up so, as you can see it's really important you get thoughs done a real interesting sort of leakage that we have found is coming out of all the ventilation for the block and beam floor so, what's happening is, we've got the slab inside the house, we've got the insulation on the inside of the wall that's to stop the cold bridging, the cold travelling through it's that gap down on the side there
that we are actually pushing smoke or air with the smoke down and it's coming out of the actual ventilation here so, absolutely key that that bit of detail gets sealed little bit more up here just to show you a little bit more smoke coming out making it a bit more interesting you can see looking up here actual smoke coming out of the blockwork all here here, here, little bit out of the trickle vents again, around the windows so, how do we stop it?
So, you can see we are obviously going to have a finished product that goes on the wall here, this is going to have monocouche or k rend or a render so, this gets completely sealed this won't be airtight as there’s plenty of detail in the gaps but air can still travel out
you really want to isolate the air from the inside not the outside so, internally again the bedding joints and the pointing needs to be spot on and smooth so you can apply a liquid membrane passive purple do a little range to seal up the blockwork wall you can obviously use pargeting coat
which is sand and cement sort of render based that you can put over a complete wall if you are using plasterboard you can obviously put plasterboard on the wall the adhesive, the dot and dabbing adhesive needs to be continuous so, when it sticks on the wall it isolates so no air can get out from the inside of the wall so, that's how you sort of overcome that problem so, hopefully you found that informative just to show you how permeable blockwork walls are.

Thanks for watching