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I would have done the concrete slab first same as your builder has and not after the rest of the build.
yes the screed needs time to dry, drying depends on how thick the screed is, 5cm thick about 6 weeks, 6cm about 8 weeks, any thicker and you can add 4 weeks per extra cm
 
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Hi Kazuya Thanks of the comment.
Anyway regardless of that i dunno how many sites youve been on, but on the ones ive been on the only part of the floor that gets done after the buildings up is the insulation then screed

12 - Wind & Watertight (Milestone)
13. Lay 1200 gauge Damp Proof Membrane over the previously cast ground bearing slab, lap perimeter up under the previously installed DPC and seal joint
14. Lay ridged insulation (This is the item the OP has advised that is being installed now prior to wind & watertight).
15. Lay screed

Is this not what my comment says above.

Below is an industry standard method that that negates the need to install the DPM & Insulation prior the the building being watertight.
dpm-under-insulation-and-screed2.jpg
 
The builders round here do it the wrong way as well, sand, DPM, concrete, insulation, screed floor covering. So you wack down the first load of concrete onto the DPM. Have you pin holed it? are there voids between the plastic and the sand? Pulled apart any taped joints?
Frank
 
They have put sand first ,then damp proof membrane ,then the insulation sheets,with a layer of cement on top .this is getting flooded every day .
 
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Someone please help me out here - Why would you ever need to install the VCL, then insulation then concrete slab then screed. The insulation should be on top of the ground bearing slab with screed on top of that...!
 
So it's wrong ? Think I'll call building control .I've paid 600.00 for their services ....
 
The OP is on about one method of construction whilst CVatcYreX is blathering about a completely different scenario.

Its all about the position of the insulation and you are just not getting it are you.
 
Someone please help me out here - Why would you ever need to install the VCL, then insulation then concrete slab then screed. The insulation should be on top of the ground bearing slab with screed on top of that...!
Only when installing UFH.
Do keep up.
 
Yes get it perfectly. It is a detail full of defects.

The correct detail.
Type one stone compacted for sub-base, Concrete ground bearing slab, Vapour Control Layer, Insulation and then screed (all constructed in the sequence highlighted in my previous post)

Pros & Cons

Pros

1. Regardless of how saturated the ground bearing slab becomes it will alway be below the Vapour Control Layer.
2. The insulation and screed are both installed when the building is watertight with a separating layer between the two to ensure moisture form the screed does not penetrate the insulation.
3. Because you are only installing a lightweight insulation on top of the VCL the risk of damage is little to none, if damage is cause you can see it.
4. Because the screed is laid in the dry and above the VCL & seperating layer its drying period is minimal as you are only waiting for the screed to dry.

Cons
None

The wrong construction detail
Sand Blinding, Vapour Control layer, Mass concrete oversite, screed.

Pros & Cons

Pros
None

Cons
1. Congratulations you have created the perfect environment for a swimming pool.
2. The Vapour Control Layer is susceptible to damage on placing concrete, of course you will never know.
2. The mass concrete oversite (subject to the weather conditions) can / in the case of the OP, become saturated full thickness and of course will be now sat within your swimming pool.
3. Once your building is watertight and the screed is laid, you know have to wait for the swimming pool, mass concrete slab & screed to dry out which I guarantee will be so in time for you install you floor finished. Who wants that amount of water below their floor.

Perhaps one person could justify the use of the above construction detail when we have more robust details.
 
Erm, I think you have misunderstood. The only thing that changes is the position of the insulation.
Everything else regards membranes etc, remains the same.

The slab, regardless of the position of the insulation, is vulnerable to the weather.
Are you actually involved in the construction industry?
 
No I'm having a extension built ,and came on her to a sk for advice
 
Erm, I think you have misunderstood. The only thing that changes is the position of the insulation.
Everything else regards membranes etc, remains the same.
You have still not responded to my point - why would you install the insulation below the concrete slab? Where is the benefit to the construction detail.? A soaking wet insulation is no benefit what so ever. In fact a wet insulation is worse than not having any?
The slab, regardless of the position of the insulation, is vulnerable to the weather.
Yes, Agreed the slab will alway be vulnerable to the weather, but with the VCL above the slab the moisture content / water will always remain outside of the fabric?
Are you actually involved in the construction industry?
Yes - I have a degree in construction and you have still not substantiated your comments?
 

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