Grosey Posted January 10, 2017 Share Posted January 10, 2017 Hi, everything I can find online in relation to screed drying times is regarding when the final floor finish can be laid. I want want to know how soon after a screed is laid (both liquid flowing and sand/cement) can I start to build up my studwork, particularly fixing sole plates using a gripill & thunderbolts? Link to comment Share on other sites More sharing options...
MrP Posted January 10, 2017 Share Posted January 10, 2017 Depends on the screed but most cementitious products tend to achieve between 50-75% of strength after 7 days so should be good for a decent fix after a week. Just do a couple of test fires somewhere out of the way and see how you get on. Just remember a dpc under the sole plate to protect from damp 1 Link to comment Share on other sites More sharing options...
Gimp Posted January 10, 2017 Share Posted January 10, 2017 Funny I was just about to ask a question on screed, but to answer your question according to this website its 24-48 hours before you can walk on it. Link: http://www.easymixconcrete.com/resource-centre/screed-faqs/ So I guess myself I would leave it at least a couple of days to be sure, test it before starting work and go easy on laying timber on it and avoid dropping tiber down on it, but that's just me. Anyway, my question which might be of use to you is, 'Does anyone here have any experience of using screedboard?' I've looked up the technical details and they vary. I'm looking to using screedboard with beam & block without any poured screed underneath. Does anyone know how this fairs, whether its acceptable to Building Inspectors? The problem I have is for first floor that will also be beam & block the floor once built is set at that height and will not really be possible to change it. I have designed it so it is built on the top of blockwork at the walls. I could lower the beam & block floor a little and say put some insulation in to give me some leeway if it ever needed changing for a floor finish greater than the 20mm approx of screedboard. However this would entail using two layers of brick in the outer wall instead of a layer of dense concrete block to take the beam & block floor down approx 75mm ish. This would be more time consuming and expensive, so I was wondering if anyone has used or heard of screedboard being directly laid on beam & block floor after grouting? (the stairs unfortunately can't be changed to adjust, they are at the maximum permissible) Theoretically I'm guessing the sensible thing to do is go with the brick option and lower the floor a touch as it at least provides a scope in case I later find I need a thicker floor finish? Link to comment Share on other sites More sharing options...
Lee Morton Posted January 10, 2017 Share Posted January 10, 2017 Hi, would it not be easier to build your studwork on a thick gauge dpc and then fixing to your screed with some sort of mechanical anchor, i.e thunderbolts. This would eliminate any chance of moisture tracking through into the timber. Link to comment Share on other sites More sharing options...
Onoff Posted January 10, 2017 Share Posted January 10, 2017 I know nothing about fixing frames like this but would resin anchors not be better? No expansion to crack the concrete etc. You've got to be organised though to do a run so as not to waste nozzles! Link to comment Share on other sites More sharing options...
Nickfromwales Posted January 11, 2017 Share Posted January 11, 2017 Screed will be soft as butter 24 / 48 hrs after laying. You need at least 2 days before walking / heavy traffic ideally. Thunderbolting into screed that's less than a week old will be useless as the bolts will just turn into drill bits and tear the screed out. As far as grip fill ( GF ) is concerned, you'd need to put some under the DPC and on top to get any actual purchase as the DPC will separate the timber from the screed. If I was looking for any kind of bond TBH I'd use D4 PU glue not GF as it expands to fill the voids, stays 'open' much longer than GF and is far quicker to work with. GF would be a last resort for me, if I didn't have anything else in the van . I take it there's either no UFH or no Ufh pipes at the sole plate positions? Link to comment Share on other sites More sharing options...
Grosey Posted January 11, 2017 Author Share Posted January 11, 2017 (edited) 2 hours ago, Nickfromwales said: Screed will be soft as butter 24 / 48 hrs after laying. You need at least 2 days before walking / heavy traffic ideally. Thunderbolting into screed that's less than a week old will be useless as the bolts will just turn into drill bits and tear the screed out. As far as grip fill ( GF ) is concerned, you'd need to put some under the DPC and on top to get any actual purchase as the DPC will separate the timber from the screed. If I was looking for any kind of bond TBH I'd use D4 PU glue not GF as it expands to fill the voids, stays 'open' much longer than GF and is far quicker to work with. GF would be a last resort for me, if I didn't have anything else in the van . I take it there's either no UFH or no Ufh pipes at the sole plate positions? Correct, UFH will be installed away from all soleplate areas. This is a block and beam 1st floor, are you suggesting the DPC as you are assuming this is ground floor, or because I need to protect the soleplate from the moisture leaving the screed? When I say gripfill I basically mean some form of glue, haven't got any further in to specifics yet? Looks like general concensus is 7+ days of screed drying before I place any sort of mechanical fixing in to it? And the longer time the better? Edited January 11, 2017 by Grosey Link to comment Share on other sites More sharing options...
Nickfromwales Posted January 13, 2017 Share Posted January 13, 2017 Yes, An assumption of ground floor, sorry. Re the moisture from the screed, at the very worst you'd benefit from treated timber for the sole plates IF you start the framework before the screed has fully dried ( about a day per 2mm unless it's stated other ). If the screed is surface dry then most adhesives would work but I particularly dislike GF as it forms a skin pretty much as your applying it ?. If the house is slightly cold / humid then it's really unsuitable TBH. Fwiw, single part PU actually benefits from moisture and it helps it cure. Link to comment Share on other sites More sharing options...
Grosey Posted January 13, 2017 Author Share Posted January 13, 2017 2 hours ago, Nickfromwales said: Yes, An assumption of ground floor, sorry. Re the moisture from the screed, at the very worst you'd benefit from treated timber for the sole plates IF you start the framework before the screed has fully dried ( about a day per 2mm unless it's stated other ). If the screed is surface dry then most adhesives would work but I particularly dislike GF as it forms a skin pretty much as your applying it ?. If the house is slightly cold / humid then it's really unsuitable TBH. Fwiw, single part PU actually benefits from moisture and it helps it cure. Any chance you could post a link to the type of glue you are sugggesting? Google is offering me quite a range. I'm assuming you mean the same stuff my chippies have used to install my caberdek t&g flooring in the roof? Link to comment Share on other sites More sharing options...
Onoff Posted January 13, 2017 Share Posted January 13, 2017 (edited) This? http://www.toolstation.com/shop/p61864?table=no Still debating whether to ditch the D3 Gorilla Glue I've got for my bath carcassing and get some of this D4. I've used it loads over the last few years but the last lot turned into a rubbery white mass in the (new) bottle for some reason. Edited January 13, 2017 by Onoff Link to comment Share on other sites More sharing options...
Grosey Posted January 13, 2017 Author Share Posted January 13, 2017 Onoff that's one I was looking at too, but then saw this one which specifically states it's PU - http://www.toolstation.com/shop/Adhesives+%26+Sealants/d180/Wood+Adhesive+%26+PVA/sd3198/Polyurethane+Wood+Adhesive+750g/p52489 Link to comment Share on other sites More sharing options...
Onoff Posted January 13, 2017 Share Posted January 13, 2017 The technical data sheet says it's not a conventional pu: http://www.everbuild.co.uk/D4-Wood-Adhesive Link to comment Share on other sites More sharing options...
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