Moonshine

traditional vs liquid screed

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For ground floor i am doing a block and beam floor, 150mm PIR insulation, and UFH within the screed.

 

I have initial drawn in 75mm screed, however i have been reading that i could reduce this down to 50mm with liquid screed.

 

Reading up on liquid screed it may cost a little extra than tradition with labour being cheaper, but as as my ground floor is actually at first floor level from the front, this may be a big plus as the liquid screed can be pumped up easily.

 

What are peoples views on traditional vs liquid screed?

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My builder used liquid screed as he said it worked out cheaper and quicker than labour for a trad screed.

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1 minute ago, Moonshine said:

For ground floor i am doing a block and beam floor, 150mm PIR insulation, and UFH within the screed.

 

I have initial drawn in 75mm screed, however i have been reading that i could reduce this down to 50mm with liquid screed.

 

Reading up on liquid screed it may cost a little extra than tradition with labour being cheaper, but as as my ground floor is actually at first floor level from the front, this may be a big plus as the liquid screed can be pumped up easily.

 

What are peoples views on traditional vs liquid screed?

Anhydrite has a residual laitance which needs to be removed over the entire area if bonding ANYTHING to it. 
Bedtime reading.

Dry screed or possibly liquid concrete with small aggregate for me. 
Are you on gas or ASHP

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7 minutes ago, Nickfromwales said:

Are you on gas or ASHP

 

I heard about that and the only place we would go for tiles is in the kitchen so may need to deal with that then.

ASHP proposed to feed the UFH

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Liquid screed is about 30% more expensive 

Extremely flat 

The biggest advantage is the drying out 

We leave for seven days then tile

Tradition needs a day per mil

75

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I decided to go traditional 80mm thick, I have seen three liquid screeds in the last year and I wasn’t overly impressed with any of them, mine would have been £2000 dearer to use a flow screed. 

The price increase is because it saves you time. 

I wanted weight to pin the insulation down with no bounce. 

 

Very impressed with mine. 

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37 minutes ago, Russell griffiths said:

I decided to go traditional 80mm thick, I have seen three liquid screeds in the last year and I wasn’t overly impressed with any of them, mine would have been £2000 dearer to use a flow screed. 

The price increase is because it saves you time. 

I wanted weight to pin the insulation down with no bounce. 

 

Very impressed with mine. 

I laid a traditional in ours 

Drying out wasn’t an issue as I laid it a soon as we were watertight 

 

The prep work for liquid needs to be spot on 

I’ve seen a few go wrong 

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hemihydrate here. Very impressive stuff.

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Might a low-water 'traditional' screed such as Tarmac Truscreed be an option? We had it in our extension as it has a relatively short drying time (7 days per 25mm) and can also be laid a bit thinner than normal at around 50mm and less depending on situation.

Edited by MJNewton

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We used Cemfloor - very impressed with it.

 

50mm thick, dries fast, no laitance, very flat.

 

Edited by wozza
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I think the cement based ones look less hassle than the gypsum / anhydrite ones.  No messing if you want to tile or stick down floor finish.

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interestingly i was on site today and was having a look at builds going up, and particularly that they had some detached house plots with beam and block which were already screeded with concrete without any external walls or roof. Speaking to the site manager this is how they do it even with UFH in the screed.

 

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I presume with the concrete screed exposed to the elements isn't too much of an issue.

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I think that's how they did our house, with just then a thin levelling compound at the end to neaten up the surface for covering. 

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23 hours ago, Moonshine said:

 

2001040761_20201014_130401(Large).thumb.jpg.8f98628614959948086a909814ddeee3.jpg

 

 

Just looking back at this photo I have just realised that the is no thermal insulation upstand, so there is going to be some nice thermal bridging.

 

I have been in contact with a local liquid screender who have quoted £1515 + VAT for 80m2 of 65mm depth. 

 

That is £19 per m2 which doesn't seem that bad.

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3 hours ago, Moonshine said:

 

Just looking back at this photo I have just realised that the is no thermal insulation upstand, so there is going to be some nice thermal bridging.

 

They'll have likely gone over the top of the upstand slightly thus obscuring it. I think you can see some of it exposed around the pipe in the other picture.

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On 15/10/2020 at 14:02, Moonshine said:

I have been in contact with a local liquid screender who have quoted £1515 + VAT for 80m2 of 65mm depth. 

 

That is £19 per m2 which doesn't seem that bad.

 

I got an updated quote for 50mm which is £15 per m2, which seems pretty decent

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2 hours ago, Moonshine said:

 

I got an updated quote for 50mm which is £15 per m2, which seems pretty decent

That’s very cheap, check who’s it is, avoid the gypsum stuff. 

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43 minutes ago, Russell griffiths said:

That’s very cheap, check who’s it is, avoid the gypsum stuff. 

 

There website seem to offer two brands of screed (belitex and cemfloor), interestingly the quote doesn't have details of what product its for, or a grade (e.g. C20 / C25).

 

The cheapness may be a factor that the plot is about a mile from their office! I can DM you the company to give me you opinion.

 

 

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8 minutes ago, dpmiller said:

what issue do you have with the gypsum stuff

Mechanical removal of the laitence for one. 
Then the doubting yourself whether or not you did that properly ( before you lay a fortunes worth of tiles / bonded flooring atop.....). 

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umm, are you sure about that, our screed is a hemihydrate gypsum, and has no laitence...

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16 minutes ago, dpmiller said:

umm, are you sure about that, our screed is a hemihydrate gypsum, and has no laitence...

Prob best to clarify that in your response given the minefield of options here. :P

 

Yes, have reviewed and discussed that with screed suppliers for two current projects, and as long as the subsequent layers above it are compatible then there is no mechanical abrasion to deal with. Priming, and the application of cementitious products only thereafter, as it’s just a modified anhydrite, seem to suffice. 
15-all. 

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@Moonshine what make a you think that new build was a screed. I suspect it was a self compacting concrete like I use on mine. It's pretty bomb proof, no serious laitence but not the cheapest getting on for about 150 a m3 nowadays

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16 hours ago, Moonshine said:

 

I got an updated quote for 50mm which is £15 per m2, which seems pretty decent


That equates to £300 per cubic metre... which means that from materials perspective I would go with self compacting concrete laid as early as possible as even if it is around £150/CuM as @Oz07 says it can be laid relatively quickly so I expect with labour you are talking much less. 

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