Hi, I recently had some screed installed by a local builder, approx 6 weeks ago. It's since started to show small cracks and, when I knock on these sections it sounds hollow. Where as the non cracked sections sound solid. It was about 40mm depth and was sand/cement/pva based. Now it's cracked I'm concerned it'll start to curl or get worse, and need re-doing. So I'm after a second opinion, there's some pics and a video below. Is there any rescuing this? should it get redone? Will it be ok as it is?! thanks in advance...
When you say screed do you mean a concrete base...... 40mm is not thick enough it has nothing to bond to and would need to come up and be done correctly. Depends what’s going on top, in all honesty you need to get an expert it, what room is it and why did they put 40 mm of the stuff down
It's a traditional sand and cement based screed (as opposed to a water/latex mix), I did raise my concern about the thickness, but was reassured it'd be ok when bonded to the concrete base but I suspect the bond has failed. Just unsure what to do now. It's 40mm to match up with the existing floor levels, wanting carpet to go above it (lounge).
Well pva is not a suitable bond for 40mm of concrete, it’s up to you what you do, you can rip it up and use a rapid set type of screed but will be expensive see http://www.instarmac.co.uk/wp-content/uploads/2016/05/UltraFloor_Fill_IT.pdf
Or rip it up and use an appropriate bonding agent to bond the concrete mix to the old underneath, I presume the builder put 40mm on top of some already solid concrete, lots of products to use, even a good bulked up floor levelling compound but would cost more
Thanks guys, appreciate the advice. Yeah, annoyingly on the research I did prior, I had asked the builder to bond the screed to the floor using SBR (I still have the email), so was a bit miffed when they used PVA, but thought they must know better. I did look into self levelling screed options but they proved fairly expensive before I even factored in getting in someone to lay it, several site suggested traditional screeds can be laid at that depth as long as they are bonded so thought it may be the way to go. From the video - do you think it's definitely failed then? Would be good to get a second opinion from some people who know what they're doing. I'll get in touch with the builder this week.
Yes its failed, needs taking up and doing again properly. Ive known some to just chuck an underlay and carpet on top but if I knew my floor was cracked it would do my head in
It was probably also the fact that in 34 years I've never met a builder who knows how to latex? Minimum 100mm for concrete.
