scottishjohn Posted November 20, 2018 Share Posted November 20, 2018 (edited) whilst in the thinking room i had a thought how about using recycled plastic timber for the sole plate along with DPC? definately rot proof --but don,t know what its insulating characteristics would be --think it might be colder than real wood. or at least use it in thin format to lift the wodden sole plate and make air gap .but sealed at outside of DPC strips ,both sides 2 layers of dpc one on slab one above plastic next to wall 2 beads of foam seal it up to make little air pocket one for you boffins Edited November 20, 2018 by scottishjohn Link to comment Share on other sites More sharing options...
Jeremy Harris Posted November 20, 2018 Share Posted November 20, 2018 The thermal conductivity of recycled plastic "timber" varies a fair bit, but would typically be around 0.3 W/m.K to 0.4 W/m.K, whereas dry softwood would be around 0.12 W/m.K, so better to use timber by a fair bit in terms of decreased thermal conductivity. The only advantage would be the rot resistance, but the big disadvantage is that the cold spot would move up to the ends of the structural studs, and as the recycled plastic would be impermeable, there would be a significant risk that it could act as a condensation locus, and stay damp. Link to comment Share on other sites More sharing options...
oranjeboom Posted November 20, 2018 Share Posted November 20, 2018 (edited) What I did with my sole plate was to attach it to Marmox insulating blocks. there's also Foamglass blocks you could use (which I found to be a bit more 'brittle' in that any gorilla onsite could easily take a few dinks out of them). To further reduce condensation risk, I will be insulating the outside of the SIP panels with additional insulation - an 'insulation skirt' around the sole plate on the exterior side. You could also ask your SIP supplier for advice, but likelihood they will just stare at you blankly. Edited November 20, 2018 by oranjeboom I forgotted something! 1 Link to comment Share on other sites More sharing options...
scottishjohn Posted November 20, 2018 Author Share Posted November 20, 2018 (edited) that stuff is serious price over £200 per sqm https://www.insulationshop.co/marmox_thermoblock_100mm.html fully insulated under slab system which comes up around it as well only runs at £85sq m think iwould go that way if spending that much on marmox something like this https://www.castleforms.com/products/raft-therm Edited November 20, 2018 by scottishjohn Link to comment Share on other sites More sharing options...
Jeremy Harris Posted November 20, 2018 Share Posted November 20, 2018 3 hours ago, oranjeboom said: What I did with my sole plate was to attach it to Marmox insulating blocks. there's also Foamglass blocks you could use (which I found to be a bit more 'brittle' in that any gorilla onsite could easily take a few dinks out of them). To further reduce condensation risk, I will be insulating the outside of the SIP panels with additional insulation - an 'insulation skirt' around the sole plate on the exterior side. You could also ask your SIP supplier for advice, but likelihood they will just stare at you blankly. Looks like a good detail. I remember the discussion with the Kingspan chap who took a while to grasp the need to keep the sole plate insulated with a bit of EWI, as I think Kingspan were struggling to understand the dynamic interstitial risk, and were just using (as does virtually everyone else) steady-state risk models. The real-world case can be pretty dynamic - I've measured a 15 deg temperature change within an hour in our cavity, with the RH rising from the low 40% region to over 90% in that time. With a cool sole plate and vapour permeable outer construction there was a substantial risk that condensation would occur, and unless enough heat energy was pumped in during the day to warm up the sole plat enough to convert the condensed water back to vapour so that it could move outwards again when the outside temperature drops, there is a significant risk that damp conditions there could prevail for some time - not good for the sole plate timber. Link to comment Share on other sites More sharing options...
oranjeboom Posted November 20, 2018 Share Posted November 20, 2018 1 hour ago, scottishjohn said: that stuff is serious price over £200 per sqm https://www.insulationshop.co/marmox_thermoblock_100mm.html fully insulated under slab system which comes up around it as well only runs at £85sq m think iwould go that way if spending that much on marmox something like this https://www.castleforms.com/products/raft-therm Not sure why they price the thermoblocks up at m2 rather than linear metres. You only have to have them around the perimeter, not as a slab system. About £19/linear metre. But worth investigating other options such as a Viking insulated raft. Link to comment Share on other sites More sharing options...
PeterW Posted November 20, 2018 Share Posted November 20, 2018 24 minutes ago, oranjeboom said: Not sure why they price the thermoblocks up at m2 rather than linear metres Most blockwork products are priced per sqm as they are normally used in that format - unusual to measure linear meterage as it depends on the height you need Link to comment Share on other sites More sharing options...
oranjeboom Posted November 20, 2018 Share Posted November 20, 2018 2 minutes ago, PeterW said: Most blockwork products are priced per sqm as they are normally used in that format - unusual to measure linear meterage as it depends on the height you need Yes, but in this case there is only one way to use them. You can't use these solely to build a wall - only suitable for one course. Link to comment Share on other sites More sharing options...
scottishjohn Posted November 20, 2018 Author Share Posted November 20, 2018 49 minutes ago, oranjeboom said: Yes, but in this case there is only one way to use them. You can't use these solely to build a wall - only suitable for one course. If you check that website I linked it says price per sqm -- £196.61 ,18blocks in a pack Link to comment Share on other sites More sharing options...
oranjeboom Posted November 20, 2018 Share Posted November 20, 2018 1 hour ago, scottishjohn said: If you check that website I linked it says price per sqm -- £196.61 ,18blocks in a pack yes, so about £19.36/metre (linear). Link to comment Share on other sites More sharing options...
scottishjohn Posted November 20, 2018 Author Share Posted November 20, 2018 55 minutes ago, oranjeboom said: yes, so about £19.36/metre (linear). still the most expensive insulation i have ever seen Link to comment Share on other sites More sharing options...
oranjeboom Posted November 20, 2018 Share Posted November 20, 2018 2 minutes ago, scottishjohn said: still the most expensive insulation i have ever seen Well you can't build a wall on most insulation. Anything 'specialist' has special prices unfortunately... Link to comment Share on other sites More sharing options...
PeterW Posted November 20, 2018 Share Posted November 20, 2018 3 hours ago, scottishjohn said: still the most expensive insulation i have ever seen You’ve obviously never seen the price of Aerogel .... Link to comment Share on other sites More sharing options...
MikeSharp01 Posted November 20, 2018 Share Posted November 20, 2018 There may also be structural issues with plastic which over time might 'flow' if under high and continuous load. 1 Link to comment Share on other sites More sharing options...
Jeremy Harris Posted November 20, 2018 Share Posted November 20, 2018 Just now, MikeSharp01 said: There may also be structural issues with plastic which over time might 'flow' if under high and continuous load. Very good point, I'd forgotten about cold flow... Link to comment Share on other sites More sharing options...
PeterW Posted November 20, 2018 Share Posted November 20, 2018 15 minutes ago, JSHarris said: Very good point, I'd forgotten about cold flow... What would be more challenging is predicting it with a reclaimed product. A lot of the recycled wood effect plastic is a mix of regrind thermoset (ie non re-melting plastics) mixed with a standard thermoplastic binder such as Polypropylene or HDPE. The issue is the voids that are created in the extrusions as it’s created, as it will have some element of bubbling occur as the regrind will create air pockets. I don’t think any of them have had any sort of testing for a BBA or similar certificate as the regrind mix is a complete unknown so certifying the end product would be a challenge. Link to comment Share on other sites More sharing options...
Alexphd1 Posted November 20, 2018 Share Posted November 20, 2018 9 hours ago, scottishjohn said: that stuff is serious price over £200 per sqm https://www.insulationshop.co/marmox_thermoblock_100mm.html fully insulated under slab system which comes up around it as well only runs at £85sq m think iwould go that way if spending that much on marmox something like this https://www.castleforms.com/products/raft-therm What's coming in at £85m2?? Link to comment Share on other sites More sharing options...
scottishjohn Posted November 20, 2018 Author Share Posted November 20, 2018 2 hours ago, PeterW said: You’ve obviously never seen the price of Aerogel .... thats cheap, it works out around £100 sqm. 1 hour ago, Alexphd1 said: What's coming in at £85m2?? someone posted they had a quote for a complete sub slab insulation that hadformed sides on it which wrapped slab right out of the ground for that money Link to comment Share on other sites More sharing options...
Alexphd1 Posted November 20, 2018 Share Posted November 20, 2018 Was that finished installed price inc concrete? Link to comment Share on other sites More sharing options...
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