ryder72 Posted March 8, 2017 Share Posted March 8, 2017 The build up on our MBC single stud timberfrme house is 140mm stud filled in with PIR insulation, airtight membrane, 70mm PIR insulation, 38mm studs, plasterboard. We need to get 3 WH toilet frames fitted. MBC's recommend is to fix the frame to the 38mm studs which line up with the 140mm studs and are screwed together with 150mm screws (effectively around 42mm deep fixing into the 140mm stud). My plumber is not at all happy with this idea mainly because this fixing is through a 70mm PIR insulation layer and instead wants to put in one 60mm timber between the 140mm studs and a second one between the secondary 70mm insulation layer. This will ensure that the whole structure is connected right through and very secure. Does anyone have a view on a robust way to fix this? Link to comment Share on other sites More sharing options...
Nickfromwales Posted March 8, 2017 Share Posted March 8, 2017 I've got some pics on the iPad. I'll post them later + method after my "high powered business meeting" ? Link to comment Share on other sites More sharing options...
MikeSharp01 Posted March 8, 2017 Share Posted March 8, 2017 1 hour ago, Nickfromwales said: after my "high powered business meeting" Is that a 30Kw condensing (liquor only) meeting or a combi (beer & liquor) meeting - now let's put 2 & 2 together and make 5, this morning the boy went off for few days and now you're in a high powered business meeting and it's international women's day.... 1 Link to comment Share on other sites More sharing options...
jack Posted March 8, 2017 Share Posted March 8, 2017 18 minutes ago, MikeSharp01 said: this morning the boy went off for few days and now you're in a high powered business meeting and it's international women's day.... Down the rabbit hole we go. Safety squints on, people! Link to comment Share on other sites More sharing options...
MikeSharp01 Posted March 8, 2017 Share Posted March 8, 2017 1 hour ago, Nickfromwales said: I've got some pics on the iPad. And I meant to add that this is a public forum not on the dark web Nick.... Link to comment Share on other sites More sharing options...
Nickfromwales Posted March 8, 2017 Share Posted March 8, 2017 High Link to comment Share on other sites More sharing options...
Nickfromwales Posted March 8, 2017 Share Posted March 8, 2017 Powered Link to comment Share on other sites More sharing options...
Nickfromwales Posted March 8, 2017 Share Posted March 8, 2017 Business Link to comment Share on other sites More sharing options...
Nickfromwales Posted March 8, 2017 Share Posted March 8, 2017 Meeting Link to comment Share on other sites More sharing options...
Nickfromwales Posted March 8, 2017 Share Posted March 8, 2017 Link to comment Share on other sites More sharing options...
Nickfromwales Posted March 8, 2017 Share Posted March 8, 2017 35 minutes ago, MikeSharp01 said: And I meant to add that this is a public forum not on the dark web Nick.... Those pics aren't free FYI. Worth every penny though . Link to comment Share on other sites More sharing options...
TerryE Posted March 8, 2017 Share Posted March 8, 2017 Keep it simple stupid. Timber fixing the studs to the 140mm studs through the top PIR will do bugger all in terms of compromising the thermal characteristics and is nice and simple -- so I would vote for the MBC suggestion. One thing that I would question is the 38 mm. If you are using the Geberit-style cisterns then they need 100mm depth though I think that you can get shallower ones. I didn't think that you'd want to start cutting these into the 70mm PIR layer but one reflection, I'd consider doing this if it were my house. So I would just fix the Wall Hung frame direct to the underlying MBC suggests. Link to comment Share on other sites More sharing options...
ryder72 Posted March 8, 2017 Author Share Posted March 8, 2017 23 minutes ago, TerryE said: Keep it simple stupid. Timber fixing the studs to the 140mm studs through the top PIR will do bugger all in terms of compromising the thermal characteristics and is nice and simple -- so I would vote for the MBC suggestion. One thing that I would question is the 38 mm. If you are using the Geberit-style cisterns then they need 100mm depth though I think that you can get shallower ones. I didn't think that you'd want to start cutting these into the 70mm PIR layer but one reflection, I'd consider doing this if it were my house. So I would just fix the Wall Hung frame direct to the underlying MBC suggests. We are using Geberit Sigma 12cm frame (120mm depth required). MBC arent suggesting going to the underlying frame but connecting to just the battens. Plumber wants to create a structure strong enough, conencted to the main studs. Link to comment Share on other sites More sharing options...
TerryE Posted March 8, 2017 Share Posted March 8, 2017 As I said KISS. Your plumber is over engineering this and you are losing living space for no good reason. I'd bolt the 12cm frame directly to the underlying MBC frame through the PIR. Why on earth not? Link to comment Share on other sites More sharing options...
ryder72 Posted March 8, 2017 Author Share Posted March 8, 2017 55 minutes ago, TerryE said: As I said KISS. Your plumber is over engineering this and you are losing living space for no good reason. I'd bolt the 12cm frame directly to the underlying MBC frame through the PIR. Why on earth not? I dont see how we are losing space. The frame will have to sit proud of the battens in any case. All he is trying to do is put in battens so that the frame is directly connected to the studs rather than indirectly through the batters. He isnt convinced that the 70mm PIR in between the battens and the studs is going to eliminate flex. Link to comment Share on other sites More sharing options...
TerryE Posted March 8, 2017 Share Posted March 8, 2017 If your over-engineering isn't going to lose you living space, then it doesn't really matter, does it?. The front frame (with the covering plasterboard) will be rigid and strong enough. The only possible flex will be in the z direction -- that is normal to the wall surface and timber fixings between the inner and MBC frames will remove this. If you do the heat loss calcs then there's is no material reason why the inner plasterboard surface needs to be more than 120 inside the /mbc frame -- that is 50mm inside the 70mm PIR inner. If you cut the Gerberit frame into the 70mm PIR inner then you might lose an exta few W heat loses but you've gained extra living space by doing so. Either you understand my point, or I am not explaining it well. Sorry. Perhaps one of the other member with an MBC frame such as @jack or @JSHarris or @Calvinmiddle should contribute their PoV, becaue I might just be in the minority here . Link to comment Share on other sites More sharing options...
Nickfromwales Posted March 8, 2017 Share Posted March 8, 2017 This is how I did them . Have a look, and I'll add some details tomorrow. 2 Link to comment Share on other sites More sharing options...
Nickfromwales Posted March 9, 2017 Share Posted March 9, 2017 @ryder72 Will your WC's be as I've pictured, eg, part height with a shelf top, or will your framework be floor to ceiling ? Do any cables or other services already reside in the counter batten spaces in the bathrooms ? I need those questions answered tbh so I can advise further, without going off down the wrong route, but at the moment I'd be looking at removing the 70mm PIR and removing all the 38mm counterbattens, and then over boarding the whole wall with 25mm ply, screwed through to the 140mm frame with 120mm self cutting heavy duty wood screws, repeated at 200mm centres. Then fix the frames directly to the plywood. ( The point that takes all the stress is the top fixings of the frame which go back to the wall, and there's a lot of 'pull' on those. If those dont get fixed properly then the frame will move and the plasterboard and tiles will move with it ). After the frames are fixed, refit the 70mm PIR over the plywood, around the WC frame, and you'll then gain around 83mm of floor space back to the room too. Is that an option? 2 Link to comment Share on other sites More sharing options...
TerryE Posted March 9, 2017 Share Posted March 9, 2017 @ryder72, I think that Nick has explained more constructively what I was trying to say: dropping from 210 PIR to 140 PIR for the 1m2 or so of the Gerberit is going to make bugger all difference to your overall heat losses, but is going to add a useful 8cm or so on one wall of your bathroom / en-suite. Link to comment Share on other sites More sharing options...
ryder72 Posted March 9, 2017 Author Share Posted March 9, 2017 TerryE/Nickfromwales - i can see where we got crossed lines. If you take a look at the ensuite next to bedroom 2 (PDF attached) you will see that there is a soil pipe in the top left corner by the shower tray. This soil pipe is going to get boxed in and the boxing will continue along the outside wall and will also hide the plumbing to the basin, waste and water to WC and concealed shower valves and the WC frame. All of this will sit proud of the 70mm PIR and the battens. We are not looking to save space since the location of the soil pipe has already 'lost' us the space. In hindsight, we should have thought of this, but hey-ho. Given that we are where we are, we want to fix the frame straight to the studs to minimise/eliminate what @TerryE cals Z-axis movement. If I interpret Nicks's photos corectly, that is what he has tried to do by cutting off the battens to gain that extra 38mm. I have also attached the wall section to illustrate. This is not the usual MBC wall build up. 1229.02.02K.pdf Typical Details.pdf Link to comment Share on other sites More sharing options...
jack Posted March 9, 2017 Share Posted March 9, 2017 We have a full width low wall with a shelf above for all of our WCs. Space wasn't an issue and we liked that look, so it worked for us. As ryder says, his build-up is different from ours anyway. Link to comment Share on other sites More sharing options...
Nickfromwales Posted March 9, 2017 Share Posted March 9, 2017 Let's answer the op then. If the 38mm battens are through fixed at regular intervals where the WC fixings reside, then I see no issue, but it is a lot to ask at such small points TBH. Adding a horizontal wall plate, as I've done with 7" timber in my pics, would straddle 3-4 of the 140mm frame studs and give you some serious rigidity. Show your plumber the pics and see if he is OK to cut sections of the counter battens out and fit a similar plate arrangement. For belt and braces I then fitted the 40x40mm UniStrut and punched timber locks through the UniStrut, wall plate, air tightness OSB layer and into the frame studs. To demonstrate how good these fixings were, I stood on the front edge of the extra long projecting WC pans, after mounting them to the frames temporarily through a disposable plywood baffle ( to represent the PB and tile layer ) and bounced up and down on them. You could park a car on them ( 3 X WC's on that same elavation ). 1 Link to comment Share on other sites More sharing options...
ryder72 Posted March 17, 2017 Author Share Posted March 17, 2017 I will post some pics of what we have done later today. For reference- BEtween 140 studs we have 1 layer of 70mm PIR. In front of this is fixed a 140*38mm timber between the vertical studs so we have the weight of the frame/toilet/user to atleast 3 vertical studs. In front of this will be the membrane will be a 70mm PIR layer and then 38mm studs. We will be cutting out the PIR and replacing it with more 140mm timbers fixed horizontally to the studs or previously fixed timbers ensuring there is complete timber to timber contract into which the frame will be fixed. Having looked at Nicks solution, I can see how this would have also worked if the 140mm timber went across multiple studs, but I also suspect I might not have got it past 4 studs given what else is going on in the bathroom Thanks very much for your help guys. Link to comment Share on other sites More sharing options...
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