What do you think of liquid floor screed?

[CalvinHobbes]

Hello, was at the Belfast sef build exhibition and the guy at te Alpha Flow Screeds was pretty convincing. He said insulation board was rarely if ever put doing right, (gaps, not staggared etc) and they worked out cheaper and were loved by building control. They gave a good saps reading and you could reduce insulation elsewhere. (parahrasing)He also said there was no problem with supply. Is there anything I should ask or be concerned about? https://alphaflowscreeds.com/floor-insulation/ Cheers

[Declan52]

You need much greater depth compared to PIR insulation to achieve the same u value.

If whoever is putting down sheets of insulation wrong then you have hired the wrong guy. There is little to no skill required for this job. 

Going by there info you would have a concrete subfloor then this flow screed then another finishing screed in top. That's a lot of concrete to buy. 

I would price up PIR insulation and compare it cost wise myself rather than believing a sales man. 

[Thorfun]

I agree with @Declan52, it really just sounds like a sales pitch. but I am a cynical b*****d.

[Declan52]

2 minutes ago, Thorfun said:

I agree with @Declan52, it really just sounds like a sales pitch. but I am a cynical b*****d.

Makes two of us then!!!

[Declan52]

Believe nothing from any sales rep unless they have the data to back it up. 

[CalvinHobbes]

Fair! Thank you, much appreciated.

 

[nod]

It’s great to tile on 

But I’ve seen a couple go wrong 

Ideally the insulation needs fixing to the floor with four knock-ins per sheet 

[Scoobyrex]

PIR is easy to lay and I think the best solution to fix ufh pipes to.  using trays of plastic strips is a pain, and the amount of times they "float" away when screed/concrete is applied.

 

If you are concerned about the PIR install, do it yourself, or be there, it is very easy and doing it yourself ensure it is taped up and complete.

[Mr Punter]

On their front page they were quoting density in kg/m².  They also had no information on insulation performance.  Avoid.

[Temp]

Sorry if this is obvious but.. Don't use insulated screed over UFH or you will wonder why your rooms are cold and your return temperatures are so high ?

 

 

[ETC]

On 15/09/2021 at 12:32, Declan52 said:

You need much greater depth compared to PIR insulation to achieve the same u value.

Agree with @Declan52You’ll need about double the amount to get the same u-value. Check with your SAP assessor before you set your ground floor build-up to make sure you’ve left enough sub-floor depth.

 

On 15/09/2021 at 12:32, Declan52 said:

If whoever is putting down sheets of insulation wrong then you have hired the wrong guy. There is little to no skill required for this job. 

You’d be surprised how easy it is not to lay floor insulation properly. Where pipes are placed below the insulation the back of the insulation is - in many cases - hacked out to let the pipes sit comfortably within the insulation and in some cases the PIR insulation is fixed through the DPM to the floor slab.

 

Solutions I see use two or more layers of insulation so that a single layer is cut between the pipes and the remaining insulation installed above and flush with the top of the pipes. But where there are placed pipes below the insulation there will always be some gaps in the insulation.

 

I have also seen insulated pipes installed above the floor slab and then just enough insulated floor screed put down to cover the pipes then PIR insulation put down on top.

 

Granny and sucking eggs but don’t forget:

That the insulated floor screed will not replace your sub-floor slab.

A DPM needs to go down before the insulated screed - and it needs to be 1200 gauge.

You will need a VCL and perimeter insulation.

Don’t fix any pipes through the DPM.

Don’t fix the PIR insulation through the DPM.