Posted: Wed Dec 16, 15 8:59 pm Post subject: Block and beam construction
Yonks ago, I knocked down a retaining wall behind my house, dug out about 5 metres back and built 2 more retaining walls at 90 degrees to each other. I then built 2 more walls perpendicular to the rear of the house and put roofs on to create a dog kennel and an outhouse.
I need to replace the OSB and felt roof, and am thinking of going for a block and beam layer topped with a living/grass roof.
I've secured a reasonable quote for the beams.
Could anyone advise me as to whether I could use aerated blocks for the infill and what to seal it with, in order to lay a living roof on top?
Are your beams to form the new roof? Loads of options for coverings, mineral felt burned on possibly the easiest / cheapest or you could use rubber, fibreglass, hot tar...
You might not need insulation? The soil & plants will provide a bit in any case. You could skip the filter layer & "protection board" as well. Something like beams, sheathing board (or sarking) building membrane, felt, drainage layer, 25mm layer clean chips, 150mm soil
Yes you can use aerated blocks, such as Thermalite Aircrete.
Personally I wouldn't let an aerated/Thermalite block anywhere near my house or any work I do. Horrible brittle things. They may be light and easy to use, but I see so many cracked walls built with them. They are too light for walls IMO.
That said, they will be ok for what you propose - just watch your step walking on them - I wouldn't trust them until covered and your load is spread.
For floors I would normally use something like Plasmoor Aglites.
Is it for weight or insulation that you are considering aerated ?
Given that the beams weigh (IIRC) 37kg/m, unless you have huge spans, the extra weight will be negligible.
If you put 3 or 4 inches of 'Celotex' into the roof covering, then the insulation properties of aerated will also be negligible.
Something like Aglites will be cheaper too.