Pocster Posted October 2, 2019 Posted October 2, 2019 OK! Related to my bathroom thread but specifically about floor and other issues. So!. We have large gaps for bath and shower tray to sit. Mainly so I can position waste and any necessary pipework. The floor as you can see is 150mm PIR then UFH screed. How should I fill these gaps once I know where my waste is going?. Just 150mm PIR and then mix my own screed? - I'm just worried the separate screed will not bond to the existing and therefore not be stable. 2nd issue is the false wall I must build to house the cistern and also hide a multitude of pipes etc. It needs to be away from the timber frame. Will this be strong enough for a timber mounted geberit frame?. Should I use steel brackets so that the false wall is tied to the timber frame for extra strength??? ( Photo shows frame and rough position of timber for the false stud wall).
Onoff Posted October 2, 2019 Posted October 2, 2019 Looks like your screed has already cracked where the two sections meet! How thick is it? Why no A142 mesh?
Pocster Posted October 2, 2019 Author Posted October 2, 2019 (edited) 5 minutes ago, Onoff said: Looks like your screed has already cracked where the two sections meet! How thick is it? Why no A142 mesh? 65mm. Yeah it has a few cracks at joints. So I could stick some mesh in my extra screed pour? ; and some fibres aswell ( to reduce chances of cracks ) TBH if I mix 'screed' it's just going to be like my concrete anyway! 1:3 (cement to sand ) ratio perhaps more water so it flows better.... Could make my screed thicker!. No mesh around but have some rebar spare so could make a rough mesh. As insulation under shower tray and bath is pointless - perhaps I could just go 50mm insulation and then screed the rest. Edited October 2, 2019 by pocster
Ferdinand Posted October 2, 2019 Posted October 2, 2019 (edited) 5 minutes ago, pocster said: 65mm. Yeah it has a few cracks at joints. So I could stick some mesh in my extra screed pour? ; and some fibres aswell ( to reduce chances of cracks ) TBH if I mix 'screed' it's just going to be like my concrete anyway! 1:3 (cement to sand ) ratio perhaps more water so it flows better.... Remember that fibres will make it a bit more difficult to spread. The one I have just had done came with pre-included fibres, and the fitter remarked (ahem) that it was tricky to spread because of the electric ufh in it. Anyhoo mine is now tiled but not grouted. F Edited October 2, 2019 by Ferdinand 1
Pocster Posted October 2, 2019 Author Posted October 2, 2019 1 minute ago, Ferdinand said: Remember that fibres will make it a bit more difficult to spread. The one I have just had done came with pre-included fibres, and the fitter remarked (ahem) that it was tricky to spread because of the electric ufh in it. Anyhoo mine is now tiled but not grouted. F Hmmmmm, ok. I need my screed to be level with existing - so perhaps no fibres - didn't realise they effected the spreadability .....
Ferdinand Posted October 2, 2019 Posted October 2, 2019 Just now, pocster said: Hmmmmm, ok. I need my screed to be level with existing - so perhaps no fibres - didn't realise they effected the spreadability ..... What my fitter said. But mine is quite a bit thinner than yours. Others’ comments?
PeterW Posted October 2, 2019 Posted October 2, 2019 8 minutes ago, pocster said: TBH if I mix 'screed' it's just going to be like my concrete anyway! 1:3 (cement to sand ) ratio perhaps more water so it flows better.... Jeez...!! No wonder you get cracking .... 6:1 is fine for screed, dryish mix as you don’t want it too wet as it takes 1mm per day to dry properly.
Pocster Posted October 2, 2019 Author Posted October 2, 2019 42 minutes ago, PeterW said: Jeez...!! No wonder you get cracking .... 6:1 is fine for screed, dryish mix as you don’t want it too wet as it takes 1mm per day to dry properly. LOL. No, the screeder did the screed (even though it has some slight cracking). It's like less than 2mm out across the entire floor! - top job! I'll do the other screed bits; but ok will reduce the cement in my mix ... ?
Onoff Posted October 2, 2019 Posted October 2, 2019 1 hour ago, pocster said: 65mm. Yeah it has a few cracks at joints. So I could stick some mesh in my extra screed pour? ; and some fibres aswell ( to reduce chances of cracks ) TBH if I mix 'screed' it's just going to be like my concrete anyway! 1:3 (cement to sand ) ratio perhaps more water so it flows better.... Could make my screed thicker!. No mesh around but have some rebar spare so could make a rough mesh. As insulation under shower tray and bath is pointless - perhaps I could just go 50mm insulation and then screed the rest. Erm...I forgot the fibres in my main floor pour (never did find the bag) but it's 100mm of 4:1 wet concrete with de aerator / waterproofing additive with A142 mesh over the whole area. The underside of the slab was in effect "castellated" as it was over Polypipe panels (saved a lot on concrete volume). It never cracked over the couple of years before I tiled. I continued the mesh into my wet room corner and when I did that I did add fibres. That was an sbr heavy concrete mix based on 10mm pea shingle after much research as I wanted a very resilient almost resinous end result. That was laid perfectly to falls using an overly complicated set of screeding angles ? Different kettle of fish to yours methinks as I've no screed in the build up. Tiled straight onto the concrete as it was dead level due to my using screed rails ei. Pleased with the whole floor in general. Time will tell when I eventually get the UFH loop connected and some heat in the slab! 1
Pocster Posted October 3, 2019 Author Posted October 3, 2019 So ! Starting on the false wall . As mentioned can’t screw through screed as ufh at the edge ( my fault ) . So ct1 in the middle - screwed at edges
Onoff Posted October 3, 2019 Posted October 3, 2019 8 minutes ago, pocster said: So ! Starting on the false wall . As mentioned can’t screw through screed as ufh at the edge ( my fault ) . So ct1 in the middle - screwed at edges I wonder if it might be an idea to drop some short bits in between that new sole plate to the existing one at the bottom of the stud wall?
Pocster Posted October 3, 2019 Author Posted October 3, 2019 17 minutes ago, Onoff said: I wonder if it might be an idea to drop some short bits in between that new sole plate to the existing one at the bottom of the stud wall? Not sure what you mean . I was going to noggin across to my new wall off the timber frame ; like this
Onoff Posted October 3, 2019 Posted October 3, 2019 1 hour ago, pocster said: Not sure what you mean . I was going to noggin across to my new wall off the timber frame ; like this That's pretty much it but I meant have the noggins level with the front sole plate so the screws aren't in shear. Neater too imo. 1
Pocster Posted October 3, 2019 Author Posted October 3, 2019 31 minutes ago, Onoff said: That's pretty much it but I meant have the noggins level with the front sole plate so the screws aren't in shear. Neater too imo. So ....
Onoff Posted October 3, 2019 Posted October 3, 2019 3 minutes ago, pocster said: So .... I meant tops level! ? 1
Pocster Posted October 3, 2019 Author Posted October 3, 2019 5 minutes ago, Onoff said: I meant tops level! ? Hmmmmmm . Well if I did it that way the timber would still need to be at an angle to meet the timber frame . My way propping it’s height up - oh ffs ! - does it matter !! ? Ran out of screws so this is where it is at the moment .
ProDave Posted October 3, 2019 Posted October 3, 2019 20 minutes ago, Onoff said: I meant tops level! ? I wouldn't do it like that, you would be screwing into the end grain of the noggin / strap, which is never very good. @pocster way I think is stronger. Plus you don't need to cut the strap to the precise length. 1
Pocster Posted October 3, 2019 Author Posted October 3, 2019 5 minutes ago, ProDave said: I wouldn't do it like that, you would be screwing into the end grain of the noggin / strap, which is never very good. @pocster way I think is stronger. Plus you don't need to cut the strap to the precise length. YES !!!! SKILLS !!! ??
Onoff Posted October 3, 2019 Posted October 3, 2019 51 minutes ago, ProDave said: I wouldn't do it like that, you would be screwing into the end grain of the noggin / strap, which is never very good. @pocster way I think is stronger. Plus you don't need to cut the strap to the precise length. Thought modern screws were designed to facilitate screwing into end grain? I pilot and glue anyway. Is MY bathroom going to fall down now? ?
Pocster Posted October 3, 2019 Author Posted October 3, 2019 55 minutes ago, Onoff said: Thought modern screws were designed to facilitate screwing into end grain? I pilot and glue anyway. Is MY bathroom going to fall down now? ? 55 minutes ago, Onoff said: Thought modern screws were designed to facilitate screwing into end grain? I pilot and glue anyway. Is MY bathroom going to fall down now? ? You mean it hasn't already????
Temp Posted October 3, 2019 Posted October 3, 2019 (edited) On 02/10/2019 at 15:22, pocster said: How should I fill these gaps once I know where my waste is going?. Just 150mm PIR and then mix my own screed? - I'm just worried the separate screed will not bond to the existing and therefore not be stable. We built platforms from pressure treated timber and WBP to set the tray into the floor slightly. Used a top access/top fitting trap but check the trap will seal against the underside of the tray before gluing it all down. Don't set top of tray flush with floor tiles or the door seal will scrape. Set it say 5mm higher. If you are going to tile the floor over any cracks or joins in screed essential to use some kind of decoupling mat or the crack will propagate through the tiles. Found this out hard way on some stone flooring. Edited October 3, 2019 by Temp 1
Pocster Posted October 3, 2019 Author Posted October 3, 2019 16 minutes ago, Temp said: We built platforms from pressure treated timber and WBP to set the tray into the floor slightly. Used a top access/top fitting trap but check the trap will seal against the underside of the tray before gluing it all down. Don't set top of tray flush with floor tiles or the door seal will scrape. Set it say 5mm higher. If you are going to tile the floor over any cracks or joins in screed essential to use some kind of decoupling mat or the crack will propagate through the tiles. Found this out hard way on some stone flooring. Appreciate the heads up . Was going to set the shower tray level with the screed floor . To avoid cracking can I not use flexible tile adhesive on the floor ; and flexible grout ??
Temp Posted October 3, 2019 Posted October 3, 2019 We used flexible adhesive and grout and it wasn't enough in our case. I suggested a decoupling mat but I would seek advice from somewhere like BAL Adhesives to be on the safe side. 1
Pocster Posted October 4, 2019 Author Posted October 4, 2019 10 hours ago, Temp said: We used flexible adhesive and grout and it wasn't enough in our case. I suggested a decoupling mat but I would seek advice from somewhere like BAL Adhesives to be on the safe side. Ok : looked at these on line . Does that mean the tiles aren’t actually bonded to the concrete ? . Or does a decoupling mat have ‘gaps’ in it to allow the tile adhesive through ? Happy to use one if it solves potential problems later ...
Pocster Posted October 4, 2019 Author Posted October 4, 2019 Stud work going good . More to add - but it certainly isn’t going anywhere !
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