bissoejosh

Thanks, I'll keep pushing! Southern have come back me within an hour and are the cheapest currently at £10.49 - pretty pleased with that as apparently prices have gone up 10% this year so far.

Which branch did you use? They've come back to me today at £11.03 for 2440x1220 despite numerous requests for 2400x1200.

Ours isn't treated to my knowledge but it hasn't been questioned either by the frame provider or BCO. We've put an extra DPC under soleplate, not sure what it does but cheap enough not to matter I guess. On top of this below the sole plate is a 2/3mm closed cell foam gasket strip. My understanding is that only external timber has to be treated and our eaves sprocket and gable ladders are so the question is obviously considered at manufacturing.

Good idea, I hadn't considered them

I'm in Cornwall, big difference in prices to what I've seen so far! I'll try those mentioned next week and see what they come back with. many thanks

I need to order 300+ m2 of 11mm OSB next week. I've had a few quotes from our local yards but wondered if anyone has recently ordered similar and would be willing to share prices so I can see how they compare and if I should be looking nationally. For reference I've been offered metric at £13.04 a sheet ex Vat. Thanks

Not sure? The fitting in photo below is directly on the top of the tank. The upper pipe goes off to the shower pump which is at floor level in the same space, the other pipe goes to the bath taps and wash basins (no issues with either). Don't believe the filters have been cleaned but also don't think the header has ever been run dry. The hot feed from the pump is getting lukewarm at best but the hot feed to the pump is piping. Is it worth taking the hot side of the pump off and seeing if their are filters etc to clean? Would adding an inline air valve at the highest point after the pump be useful?

I haven't been up to check but I presume so as all the other hot taps are fine, only those running off the shower pump that aren't happy.

No hose unfortunately, just a fixed riser. I guess i could uncouple it?

My parents house has a pumped shower setup (Salamander ESP50CPV) running an ensuite and the main bathroom. Header tank up in the loft and hot water cylinder next to the pump in an airing cupboard. For some reason the pump occasionally primes during the day but I thought this was due to the mixer being incorrectly calibrated. Yesterday the showers in both rooms stopped working other than when set on cold and the pump makes a noise very similar to cavitation - airlock? Youtube suggests a number of tricks to clear the block but I'm not having much luck and can get a trickle of hot water at either shower at best. Any advice greatly welcome!

Exactly what I mean. You've explained it much more clearly than I managed! On my build there is currently nothing beyond the joist ends except the OSB sheathing (not yet fitted) but we have a large cavity before the rain screen cladding to allow for our hidden guttering so I could very easily add upto 50mm on external insulation for this problem zone. Alternatively I could use expanding foam in the pocket around the joists which should stop the air reaching the timber. Any thoughts on which is a safer bet?

It's one of those frustratingly simple solutions you wish you'd thought of! I see a few people have started doing their own DIY version by adding an LED light above the blade housing, simple enough to do I'd imagine and 100% accurate everytime.

Apologies, badly worded on my part, to be exact its a Gerband SD airtight membrane / VCL combined. https://passivehousesystems.co.uk/product/gerband-sd-control-airtight-membrane/ It is fitted to control air leakage around the joist wall interface and I can see it doing that fine. My issue is that in theory warm air could travel into the 'fold' as it is open where the joist goes in. I think the solution is to fill this area with a closed cell expanding foam to stop air reaching the timbers, or alternatively external wall insulation for this small area to keep the joist ends above dew point. I was curious to see if the issue has been raised before on timber frame constructions as it must happen a lot. Plenty of people have mentioned using a tony tray equivalent on their TF's.

On our build we've done as others have and laid our first floor joists on an airtight membrane/ VCL which is turned up and lapped over the joist ends before tucking neatly into the first floor airtight layer. The underside will do the same at ground floor level. My question is about condensation forming towards the joist ends where they protrude towards the edge of the insulation in both upper and lower walls. Does the airtight membrane stop all air movement and therefore eliminate the risk or will warmer air still find it's way in somehow and then condense when it finds a cooler surface? I know in the US a lot is made of insulating rim boards correctly but this seems to be in situations without an airtight barrier. This must apply to a lot of TF builds or any construction type where joists carry across the walls at the 1st floor junction and I'm really wondering if the airtight membrane is a complete solution or not? Thanks

Really interesting to see this, If I ever build another house I'd like to do a DIY insulated slab much like you've done. As already mentioned the site looks great. Best of luck with the ICF!

If you'd said this 3 months ago I'd have been all ears and tried to do the same. Even a few hundred quid to an engineer to prove the loadings would surely save a fortune compared to the 'off the shelf' versions!

Now that's an interesting proposition. Would you be allowed EPS / XPS without a topping from a fire point of view? Another issue could be the camber in the beams which a screed/topping lets you grade out.

I agree. I've just done a 200mm cavity filled with batts all built myself. No chance I would let someone else do it as it's far too easy to skip the insulation detailing. If I'd known at the time I'd have done EPS beads - no covering up insulation, less cavity cleaning and so much quicker. Ply framed box sitting across the cavity and either resting on the outer leaf (10-15mm) or have it stop short. DPC wherever it touches blockwork. Window fits within the box and airtightness etc is much simpler.

That should make it a lot easier. The issue I had involved sign off for the the structure and the manufacturer complying but this was for a full structural frame. Have you seen the Charlie Luxton blog? He used i-beams over masonry for insulation. I think the issue of cold bridging through the web is pretty similar to a Larsen truss design which uses thicker section timber and balances out to an insignificant amount but I could be wrong. I-Beams are nice to work with - lightweight, straight and readily available. Cost wise I can't say as I never managed to get a truss price unfortunately. Another option could be posi joists used as wall studs? http://www.moduland.eu/posi-joist/posi-stud-walls/

How do you want to use them? As an addition to the outside of a structural wall or as the structure itself? I looked for Larsen truss suppliers but struggled so have gone down the I-Beam route which gives a very similar outcome.

TF doesn't have to have a passive slab. It's a great solution if you can do it and I wish we could but our ground didn't allow so we have beam and block on strip foundations.

OK, yes think that's clear. We'll be building our frame before screeding our floor so I'll put a strip of DPM under the sole plate and the join this to the main DPM when the floor is laid otherwise it'll get damaged during construction.

Any recommendations as I'm struggling to find anything specific for the job that isn't in the US? EPDM gasket the sort of thing you mean? Thanks, that's really useful and has helped me finalise my DPM / airtight interface.

All of the above can be applied to a timber frame house. Foundations can be exactly the same if not smaller than those for a masonry construction. Timber frames are about as traditional as you can get and certainly don't need to cost a huge amount.

I've got a small area of wall with two skins of block/brick with a gap 15-20mm that I want to fill with insulation, it's below DPC so I don't think mineral wool etc. Current idea is either spray foam or loose EPS beads/shavings. Any other options I might of missed?