Floor insulation perimeter installation? (block build)

[vfrdave]

@dpmiller not sure what screed you are putting in, I am putting cemfloor down by CES. I checked with them recently and they said pir around perimeter walls and my choice of pir or 8mm foamed roll on internals.

PIR all round may be the more expensive option, haven't priced it up yet.

Edited March 10, 2019 by vfrdave

[dpmiller]

Ta Dave. I think we'll be going with RTU but there was next to damn-all between the two quotes...

Did they say anything about doorway joints? RTU have priced expansion strips but I haven't seen much guidance on where they're needed.

[Declan52]

I put them on at every door way.  Nothing fancy like a strip,  the  screeder just used his trowel to  cut into the sand cement mix and leave a slot.  If your going for the liquid type then I presume you need a proper strip. 

[vfrdave]

@dpmiller yes CES will put in doorway joints on the day of pour wherever they deem necessary. I believe it is just a bit of rigid or corrugated plastic.

[Brickforce69]

Had cemfloor installed in November over 2 floors . UFH went on at the end of January and have large cracks at every doorway,some cracks 6 ft long going into the middle of the floor. Contractor been back to fix cracks with resin but completely pissed off with the finished result!

Heating temp increased 2 degrees every second day so this isn’t the cause,just bad workmanship through not installing joints at the doorways. Any one else had problems with cemfloor?

[vfrdave]

Haven't had mine done yet but joints in doorways is a must.  Where about a was your install @Brickforce69

[Brickforce69]

Install in my house in Scottish Borders. My warranty guy asked for joints in the doorway but they were adamant they weren’t required with this product. Tbh,I presumed the floor would be smooth enough to lay the lvt straight on to but the flooring contractor says it will need a further screed at a cost of £1300 on top of the £4200 I’ve paid for the cemfloor.

Did my last house with sand cement myself and had minor hairline cracks but nothing like this. Tried to get McGrath’s Congress involved who supply the aggregate but they want nothing to do with it. One expensive f**kup!

[Nickfromwales]

8 hours ago, Brickforce69 said:

Install in my house in Scottish Borders. My warranty guy asked for joints in the doorway but they were adamant they weren’t required with this product. Tbh,I presumed the floor would be smooth enough to lay the lvt straight on to but the flooring contractor says it will need a further screed at a cost of £1300 on top of the £4200 I’ve paid for the cemfloor.

Did my last house with sand cement myself and had minor hairline cracks but nothing like this. Tried to get McGrath’s Congress involved who supply the aggregate but they want nothing to do with it. One expensive f**kup!

LVT should never go straight down, and I’ve never seen it done. The result would be terrible ?. 

Leveling with a feathering ( fine SLC ) compound is part of the installation as a rule so that cost should be lent to the laying of the flooring and not reflect on the total cost of the screed .

LVT is simply too thin to even dream about putting it straight into a slab. 

 

You even have to plywood and feather over chipboard / other timber decks prior to LVT going down. 

[Brickforce69]

I get that about the feathering but the claims from Cemfloor that it’s laitance free and perfectly level lead me to presume that it might be good enough for the lvt. All I would say is that it’s a lot quicker to install but the contractors  have let me down badly with not having any crack control at the doorways so an expensive lesson learned!