karenw

Hi, Remodelling/extending a 1970's house, as much DIY as possible. Putting in water UFH throughout. to replace a really old radiator system. On the ground floor we currently have a suspended timber floor in the existing house and were going to do a suspended concrete beam and block in extensions with lewis deck/screed in existing house. However, joists on ground floor are not strong enough for this and when preparing the site we have discovered a huge concrete slab externally under patio slabs that is 150mm deep and covers most of the extensions areas. The depth from this to dpc is approx 340mm. In addition, we have a void of 240mm from dpc to a concrete oversite in existing house. So we have changed our minds and think insulation, concrete slab and screed makes more sense. The questions we have are: 1. As we have a lot of solar gain, we were considering putting insulation under concrete to take advantage of the thermal mass with anyhdrite screed over ufh pipes for self levelling and efficiency. We can't seem to figure out how to fix pipes to concrete if we do this and ufh companies we have asked advise against doing it because of the lag in heating effectiveness. We know this but think gains outweigh disadvantages for us. Has anybody put insulation under concrete and how has it worked out and any advice on fixings to use ? 2. Putting ufh in concrete and not having screed? Concerned about levelling floors and efficiency. Are there any other advantages apart from thermal mass, saving cost of screed? Finished floors likely to be tiles. Was considering polished concrete a long time ago but costs scared us off unless it could be done diy when ufh is in the concrete. Is this done by fixing to mesh or any other ways? 3. First floor of existing house: was going to use lewis deck and screed as want to use wet ufh. Now considering dry screed boards such as screedboard20 or knauf brio to save drying time etc. Has anybody used these? Do they live up to their claims that they are more efficient than a wet screed? Any other cost effective ideas for first floor water underfloor heating? The space is open plan and a vaulted ceiling so no concern about height build up, although we need to tie in a flush floor with the roof terrace of the single storey extension at the rear. I know you pay your money and take your choice to a certain extent but when there are so many options out there it is helpful to hear other people's experiences and hindsight. If this has already been discussed, happy to be pointed to the post but I tried to look and there are a lot of ufh posts. Thanks, Karen

Hello all, I've been aware of this forum for quite a while and have often disappeared down a rabbit hole for hours on end when searching for answers to questions, going off on various tangents! I have met some members on a training course by Insulhub in Feb 2019 I think-Sue B, Tom's barn, Jamie from Insulhub. I said I was going to join but am only just getting around to it, which speaks volumes. We are remodelling/extending our 1970's detached house on Hayling Island (PO11). We are trying to do it as cheaply as possible (in terms of cost not quality) so doing as much of the work ourselves, bringing in skilled trades as and when necessary. We are fortunate that we have a builder as a brother-in-law and a nephew who is a plumber, although they do not live locally, who are happy to offer advise on technical issues and are already hand holding and proving very useful. We are an accountant and an engineer, although around twenty years ago we did finish a barn conversion from shell stage that we had bought off a builder who had gone into liquidation. So we have some experience of the process. I have drawn the plans myself to save costs and we gained planning permission around two years ago, so don't laugh or be too critical! The project was put on hold for a while but we are now back on it and have done most of the site preparation and demolition, appointed building control and are in the process of appointing a structural engineer . I am currently working through the building regs drawings, some of which are proving to be a bit more technically challenging than others. We are, however, persevering as we need to solve the practical building issues anyway so might as well draw what we're planning to do. No doubt this forum will be a great help with these areas. I have attached some drawings so you have an idea of what we are planning to do and are planning to build the extensions ourselves, most likely with Isotex ICF, provided the re-quote is not wildly different from the original. We are hoping to set out and start foundations and drainage over the weekend. The first technical questions regarding drainage design/plans and first floor roof terrace flush with first floor of existing house will follow almost immediately. Karen and Adrian Winterlake Remodel-Drawing No. 001 Proposed Elevations.pdf Winterlake Remodel-Drawing No. 002 Proposed Ground Floor Plan.pdf Winterlake Remodel-Drawing No. 003 Proposed First Floor Plan.pdf Winterlake Remodel-proposed-front view image.pdf Winterlake Remodel-proposed-rear view image.pdf