Browse Forums Renovation + Home Improvement 1 Jun 03, 2013 10:57 pm Hi there, i am new to this forum and am looking for some help and also to provide some assistance where i can. I am looking to extend out the back of my existing home, the extension is about 100m2 and basically involves kitchen, dining and living. My house is in Sydney and is built on a slight sloping block. The idea is that the extension is to be a gentle split level so going down 4 steps. My issue is that i would like to have a suspeded concrete slab in the new extension part of the house. The rest of the house is on floor boards with a 400mm - 900mm cavity under the house. As i mentioned its on a slight sloping block. The issue with the suspended slab idea is that because i want hydronic floor heating in the new area, i am at a loss to know how i can insulate this slab. Reason being is that because the new area is a split level, the cavity under the slab will be between 300mm to 600mm, so access to insulate is near impossible. I am planning on using something like a bondek and would like to insulate the top of the bondek prior to pouring the concrete. I dont see any other option, but have not seen something like this done. The reason it needs to be suspended is because i am on clay and have moisture issues as present. The last thing i want is to have slab in contact with moisture. Has anyone ever had this issue, has anyone got any ideas? The only other issue i have is to perhaps excavate more to enable more service space but this doesnt seem sound either. Any help appreciated Rod Re: Suspended Slab Insulation HELP! 2Jun 04, 2013 12:00 am I did some searching a while ago and at the time found several manufacturers of insulation for use under slabs, ie on top of your Bondek. Unfortunately I didn't bookmark. Lots of others for under floor, but the Bondek might lessen the effect. Where I might be actually of help is an integrated slab and beam system. http://www.ezidek.com.au/ They seem to use a type of Waffle system that claims an R-Value of 3.5, which appears impressive. Maybe another is SmartSlab, but not sure. Both in NSW. QLD try http://www.eskydeck.com.au seems it might be normally use with ICF systems, but it uses EPS forms, so integrated insulation. Can't hurt to ask. OTH Slabs are often in contact with moist earth, at least down here in VIC Re: Suspended Slab Insulation HELP! 3Jun 04, 2013 7:52 am You could lay out polystyrene insulation on sacrificial formwork (formwork that is left in) then lay your bondek over the top. Just be careful what timber you use as formwork left in could become your termite risk. Foremost Building Expert in Australia,assisting with building problems/disputes, building stage inspections,pre-contract review advice for peace of mind 200 blogs http://www.buildingexpert.net.au/blog Re: Suspended Slab Insulation HELP! 4Jun 04, 2013 9:45 am thanks for this guys i will look into it. I did think about the sacrificial formwork with insulation and then bondeck but termite risk is real. House across the street was destroyed aswe live in a bushy area. Regards Rodney Fair Trading can issue orders to rectify and complete but once the matter goes to NCAT these orders are automatically vacated. You will have to terminate contract and sue… 21 29752 How are you doing Ben? Extremely interested in hearing what you are doing or plan to do! 12 15170 Hey guys building a new place through a volume builder and just wondering if i should complain to the site supervisor as we just had plasterboard installed. Looks like… 0 11277 |