GrantMcscott Posted June 7, 2021 Share Posted June 7, 2021 (edited) how do you measure screed thickness is it from the insulation height to the top of the screed or from the top of the pipes to the top of the screed. At the minute I have 75 mm from insulation to top of screed. Is this to thick? thanks Edited June 7, 2021 by GrantMcscott Link to comment Share on other sites More sharing options...
MarkyP Posted June 7, 2021 Share Posted June 7, 2021 it is the total thickness of the screed so, yes, measure insulation to top of screed regardless of pipework. If sand and cement screed then 75mm is about standard. Liquid pour is thinner. I used liquid at about 60mm, personally I find it a bit bouncy on the insulation and it doesnt have a completely solid feel, the kids thumping around can be felt through it. If I had my time again I would have gone with my 150mm concrete slab over the insulation and had the concrete laid to a decent standard of flatness/level and done away with the screed entirely. I havent done sums but reckon the higher spec slab finish is more than covered in the screed savings. Then I would have put finish floor over, or run a smoothing compound if it was a bit rough, then finished. Slab would possibly need some structural movement joints depending on what you want to put over the top of it. Link to comment Share on other sites More sharing options...
Thorfun Posted June 7, 2021 Share Posted June 7, 2021 (edited) 1 hour ago, MarkyP said: If sand and cement screed then 75mm is about standard. this is what I thought as well but I was talking to an old plasterer/screeder and he said that sand and cement screed can be thinner if you put chicken wire in the screed!! not sure if he was winding me up or not though. I guess anything is possible. ? @nod you ever heard of this? Edited June 7, 2021 by Thorfun tagged nod for comments Link to comment Share on other sites More sharing options...
markc Posted June 7, 2021 Share Posted June 7, 2021 5 minutes ago, Thorfun said: this is what I thought as well but I was talking to an old plasterer/screeder and he said that sand and cement screed can be thinner if you put chicken wire in the screed!! not sure if he was winding me up or not though. I guess anything is possible. ? Chicken wire will act as reinforcing and hold the screed together/stop it cracking, but do you really want or need to cut down on the thickness? As @MarkyP pointed out, reducing mass of a floor generally results in more movement. Link to comment Share on other sites More sharing options...
Thorfun Posted June 7, 2021 Share Posted June 7, 2021 38 minutes ago, markc said: Chicken wire will act as reinforcing and hold the screed together/stop it cracking, but do you really want or need to cut down on the thickness? As @MarkyP pointed out, reducing mass of a floor generally results in more movement. nope. just thought I'd mention it as I was having a discussion with the guy between Anhydrite screed (which we've been specified) at 50mm and sand and cement at 70mm. thought it was interesting that it's normally stated that 70mm minimum for sand and cement but with the chicken wire (or possibly fibres added to the mix) you could go thinner. Link to comment Share on other sites More sharing options...
nod Posted June 7, 2021 Share Posted June 7, 2021 49 minutes ago, Thorfun said: this is what I thought as well but I was talking to an old plasterer/screeder and he said that sand and cement screed can be thinner if you put chicken wire in the screed!! not sure if he was winding me up or not though. I guess anything is possible. ? @nod you ever heard of this? We used to put chicken wire in all the time Mainly when going over groups of pipes In the days before there where fibers added to the screed Ideally you need 50 mil of screed Though I’ve tiled floors that have barely covered the UFH pipes Link to comment Share on other sites More sharing options...
GrantMcscott Posted June 7, 2021 Author Share Posted June 7, 2021 Ok so my 75 mm is OK for sand and cement screes and id I want 25 mm more insulation and quicker drying I use the liquid screed. Is there any benifit laying the liquid screed at 75 mm? Link to comment Share on other sites More sharing options...
Mr Punter Posted June 7, 2021 Share Posted June 7, 2021 40 minutes ago, GrantMcscott said: Is there any benifit laying the liquid screed at 75 mm? No most of the liquid screeds are fine at 50mm so the 25mm would be best as insulation if you want liquid. The cement based ones are easier to tile than the anhydrite ones. 1 Link to comment Share on other sites More sharing options...
DragsterDriver Posted June 7, 2021 Share Posted June 7, 2021 Cement based everytime with liquid screed. Link to comment Share on other sites More sharing options...
GrantMcscott Posted June 7, 2021 Author Share Posted June 7, 2021 Not sure what you mean u recommend cement based over liquid? Link to comment Share on other sites More sharing options...
GrantMcscott Posted June 7, 2021 Author Share Posted June 7, 2021 2 hours ago, DragsterDriver said: Cement based everytime with liquid screed. Not sure what you mean u recommend cement based over liquid? 1 Link to comment Share on other sites More sharing options...
Adam2 Posted June 7, 2021 Share Posted June 7, 2021 17 minutes ago, GrantMcscott said: Not sure what you mean u recommend cement based over liquid? good article here which will enlighten 1 Link to comment Share on other sites More sharing options...
DragsterDriver Posted June 7, 2021 Share Posted June 7, 2021 1 hour ago, Adam2 said: good article here which will enlighten Yeah- the prep for tiling is pretty hardcore. Others may vary but the tilers I use just won’t entertain the anhydrate any longer. Too many problems. 1 Link to comment Share on other sites More sharing options...
GrantMcscott Posted June 9, 2021 Author Share Posted June 9, 2021 just out of intrest has anyone used an alternative to floor screed for UFH like High Density Dry Screed Panels Link to comment Share on other sites More sharing options...
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