Gary Martin

150 sq mt dormer bungalow. was looking at timber frame as faster warm up and air tight. Heard of some with rot in base after a few years. ( I know it shouldn’t but it did ) I then considered cavity block for longevity but a slower warm up and difficult to get air tight. as insulation is essentially “inside” with TF, but “outside, in the cavity” with block, I thought it made sense to get the best of both methods. my plan, from outside in = timber cladding, batten& counter batten ( gives 50 mm air gap ) breather membrane, block, 50 mm cavity,block, 100 mm celotex, air Barr membrane, battens fixed through to blocks, plasterboard and skim. I looked at SIPS and ICFs but the “ none standard construction “ label makes mortgage or resale more difficult. I assumed the cavity block bit would be classed as standard construction and the siting of the insulation arbitrary. ??????

Up date on my supply. western power put a new pole on my land, and ran a cable to it from the neighbours pole. 70 meters WP sorted out the wayleave. they supplied ducting and a meter box. I had to dig a trench, place the ducting, plus drawstring, and fix meter box for temporary supply. They then ran cable from the new pole, underground for 20 meters and connected to the new box. £ 7,000

Thanks G&J. Could you expand please? I’m new to self building and keen to learn. thanks

Cavity for weather protection. Surely if insulation is held tighter against internal skin, there is no gap to slow condensation, also the celotex acts as a secondary vapour barrier to supplement a fully sealed one. any moisture in the blocks could dry out via the ventilated cavity. ? ps MVHR system will also be fitted. thanks for your comments gary

Just received PP to demolish a part Q agricultural building and build a smallish bungalow. In Cornwall im still debating construction methods. Any suggestions? got electricity for £10k and water for £10 k septic tank planned for sewage. gary

Could I build a new house with 50 mm uninsulated cavity block walls, with, say, 100 mm of celotex/ kingspan fixed to the inside walls, then service battens,vapour barrier, plasterboard and skim. would it pass building regs ?