Rich Posted October 21, 2018 Share Posted October 21, 2018 Hi all I am looking for a little help if possible. After meeting with our Architect today I have been left with more questions than answers. Our house is being built on driven piles and therefore a ring beam with block and beam on top. The floor make up has been specified as follows: Block and beam, DPM, 100mm "celotex rigid insulation", (already looking to increase this to 150mm) 50mm Screed. I enquired as to how I will achieve the required 100mm step down into the garage, the solution? remove the insulation from the garage floor build up. Now I appreciate this is a simple solution however it doesnt really sit right with me for the a few different reasons: Ideally I wanted underfloor heating in the garage, wanting the garage to be part of the thermal envelope of the building as it is integral, last but not least there will be an internal door to enter the garage off our hall, which i would rather not have an cold room on the other side of. Now after a bit of research (found a few relevant threads on here) the step down can be replaced by a slope away from the internal door. However whilst this subject was being discussed with the architect he suggested the floor makeup with insulation may not even be up to the job for the garage. Have any of you found your self in this situation? If so how did you get around it? at the moment I am thinking sufficient reinforcement to the screed layer or maybe 100mm insulation in the garage (upping to 150mm in main house) which would allow a thicker screed/concrete layer in the garage. I have attached some drg's for reference. Link to comment Share on other sites More sharing options...
nod Posted October 21, 2018 Share Posted October 21, 2018 I personally wouldn’t put insulation on the garage floor If you are likely to have your car in there You should find that your B&B design will have deeper beams in the garage area for this reason Link to comment Share on other sites More sharing options...
Rich Posted October 21, 2018 Author Share Posted October 21, 2018 12 minutes ago, nod said: I personally wouldn’t put insulation on the garage floor If you are likely to have your car in there You should find that your B&B design will have deeper beams in the garage area for this reason The beam and block design seems to use the same.beams (155mm) just at reduced centres. in all reality it's unlikely to be used for a car during our time here, more of a workshop/store. Link to comment Share on other sites More sharing options...
PeterW Posted October 21, 2018 Share Posted October 21, 2018 Concrete needs to be 100mm in the garage - preferably with rebar or mesh in it as 50mm isn’t that thick to park anything on. Link to comment Share on other sites More sharing options...
Rich Posted October 21, 2018 Author Share Posted October 21, 2018 13 minutes ago, PeterW said: Concrete needs to be 100mm in the garage - preferably with rebar or mesh in it as 50mm isn’t that thick to park anything on. Thanks for the input, that can be achieved if I put 150mm insulation in the main house and then 100mm with 100mm of screed in the garage. Would standard "celotex" be fine for under the 100mm screed in the garage? Or is there a specific "high load" insulation? Link to comment Share on other sites More sharing options...
PeterW Posted October 21, 2018 Share Posted October 21, 2018 Standard would be fine - it’s got so high a load spec and the concrete would spread any point load. 1 Link to comment Share on other sites More sharing options...
AliG Posted October 21, 2018 Share Posted October 21, 2018 (edited) It is not recommended to heat a garage if you keep a car in it, it is not considered to be good for a car. TBH a modern car can be left outside happily for years, so it doesn't make much difference. Realistically a garage door is not well insulated or sealed and heating a garage is going to be an enormous waste of money, especially if you actually use the garage and regularly open the door to let the car in and out. My current and last house had integral garages with the same insulation as the house in the walls, but no insulation under the floor. Then an insulated sectional door. The garage tends to stay at around 10-11C when it is around 0 outside. This makes all the difference when you get into the car in the morning. A better idea is to make sure that the door to the garage is well sealed and insulated, use the saving from not buying the Celotex below the garage floor. It is no different to all the other doors and windows in the house that have the cold outside on the other side, indeed it will still be warmer in the garage than outside. Heat loss is driven by the temperature differential which won't be that high between the house and the garage. My last house just had a normal room door between the garage and the house with intumescent seals, the hall this was in lost a lot more heat through the side door to outside. One slightly awkward thing is getting an insulated fireproof door that you need for an integral garage, but it is doable. Edited October 21, 2018 by AliG Link to comment Share on other sites More sharing options...
ADLIan Posted October 21, 2018 Share Posted October 21, 2018 Check loading with insulation manufacturer. Celotex (and probably other pur) is BBA approved for domestic type loadings only. XPS has higher compressive strength and often used in areas subject to vehicular access. Link to comment Share on other sites More sharing options...
wozza Posted October 22, 2018 Share Posted October 22, 2018 Just thinking outside the box, Could the garage be insulated under the block and beams? Link to comment Share on other sites More sharing options...
vfrdave Posted October 24, 2018 Share Posted October 24, 2018 I have been struggling with this mail me as well. The head says to insulate but so much conflicting advice about suitability of insulation under floor. I think @AliG has made my mind up to not insulate the garage floor. Link to comment Share on other sites More sharing options...
joe90 Posted October 24, 2018 Share Posted October 24, 2018 I also conflicted with this and without any other insulation in the garage, metal roof and no heating I can’t see how insulation will raise the temperature , the floor will surely balance with the air temperature. Link to comment Share on other sites More sharing options...
Geoffers1251 Posted January 22, 2020 Share Posted January 22, 2020 I know it's a while ago now but I am in the same boat when it comes to insulating and heating the block and beam integrated garage floor. I was wondering what the out come was with yours. Link to comment Share on other sites More sharing options...
sean1933 Posted February 2, 2020 Share Posted February 2, 2020 On 22/01/2020 at 12:29, Geoffers1251 said: I know it's a while ago now but I am in the same boat when it comes to insulating and heating the block and beam integrated garage floor. I was wondering what the out come was with yours. Not sure what the outcome for the op was, but as I wanted my garage floor insulated too, I have ended up going with the Jablite garage floor system. Insulation (EPS) replaces the blocks between beams then min 75mm structural concrete + A142 mesh above. Due to place my order this week as the bricky gets going in a few weeks ? https://www.jablite.co.uk/application/garage-floor-system/ Link to comment Share on other sites More sharing options...
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