Piercing the dpm with ufh clips.

[Patrick]

Once again, a bit lost here.

As far as I understand the "best" or typical setup on a block and beam floor with ufh is something like this :

 

With from bottom to top :

 

-block and beam floor (or in my case, beam and insulation))

-top layer of insualtion

-damp proof membrane

-ufh pipes tacked into the dpm

-top screed

 

This will lead to the ufh pipes being stapled through the dpm like this :

 

 

 

Isn't this a bit of a problem? Piercing the membrane.

And generally, I'm a  bit in the dark about the different membranes (dpm, dpc, vcl, radon barrier) in the floor. I do understand how a wall setup works, and no problem with a roof, but just struggling with the floor membrane locations.

 

 

[nod]

You would normally lay a membrane over the whole floor taping any joints and Attaching the edges to the high load dpc hanging from the block work 

Then the insulation is laid with another membrane (slip) on the top 

Pipes clipped through that

Some  clip the pipes directly to the insulation 

[nod]

9 minutes ago, nod said:

You would normally lay a membrane over the whole floor taping any joints and Attaching the edges to the high load dpc hanging from the block work 

Then the insulation is laid with another membrane (slip) on the top 

Pipes clipped through that

Some  clip the pipes directly to the insulation 

Here’s some I took for BC

[Visti]

As nod mentioned, your DPC will actually be the first layer of DPM you put down before the insulation. Generally fairly high grade stuff too. The clips only pierce the thinner layer above the insulation, which is only really there to ensure an unbonded concrete/screed above

[Patrick]

Nice one  @nod

So the piercing of the membrane is not a problem?

Edit:

thanks @Visti

.
Think understood this now.

Edited November 2, 2019 by Patrick
Answer came up in between

[nod]

1 hour ago, Patrick said:

Nice one  @nod

So the piercing of the membrane is not a problem?

Edit:

thanks @Visti

.
Think understood this now.

No problem at all 

Overload of pics 

But shows the process 

[Visti]

Probably helps to point out: The DPM layer (below the insulation) is quite thick and hard(ish). The top layer (above the insulation) is almost as thick as a garbage bag, if maybe just a bit thicker. 

[Patrick]

@nod
 Loads of pictures always better for me. Tbh I sometime struggle to comprehend the amount of text in some of the topics on here. Must be because I was kicked out of school way too early and most of the regular posters on here are some serious (ex-) academics.

[bissoejosh]

For us the lower membrane below the insulation was our radon barrier (Cornwall)  so much thicker. The slip membrane on top of insulation was a very thin DPM, pierced a lot of times for the UFH but no issues whatsoever. This was just taped up the walls whereas the lower radon membrane was fully lapped and taped to the DPC as @nod mentioned.

 

Worth also thinking about how your might link your wall airtightness layer (not sure of construction) to the floor? Our wall membrane is lapped and taped to the lower radon membrane to ensuite continuity in the airtight layer. 

[Oz07]

@nod did you use those preformed corners you can get? @Patrick external corners can be a bit fiddly

[nod]

No my wife did them all and pinched a couple o rolls of render tape from me and sealed everything 

[Patrick]

25 minutes ago, nod said:

No my wife did them all and pinched a couple o rolls of render tape from me and sealed everything 

Good wife

[nod]

Just now, Patrick said:

Good wife

She if 

Office manager 

Slater 

joiner 

Renderer 

The list goes on 

[Russell griffiths]

12 hours ago, Patrick said:

So the piercing of the membrane is not a problem?

@Patrick you need some clarification on this, piercing the DPM is a big problem. 

In @nod pictures he hasn’t pierced the DPM, this is covered by the insulation, the black plastic you can see with the clips pierced through is a second layer called a slip layer, this is there to stop the screed getting between the insulation and lifting it up. 

 

You need to make it clear you you are not using block n beam but beam with insulation panels. 

 

What detail has the insulation block manufacturer recomended. 

 

And why use the insert insulation if it’s £3000 dearer than normal blocks. 

[Pocster]

Our build is more complex but we had the exact same issue that the ufh clips could not penetrate the below ground water proofing . Just used the ‘egg cup’ plastic ( forgive lack of terminology) . So ufh clipped inbetween those . Upper layer ( which is B and B ) did a membrane first , then pir - then sheet to protect pir from screed . So happily pierced that sheet with ufh clips .

Edited November 3, 2019 by pocster

[Patrick]

4 hours ago, Russell griffiths said:

@Patrick you need some clarification on this, piercing the DPM is a big problem. 

In @nod pictures he hasn’t pierced the DPM, this is covered by the insulation, the black plastic you can see with the clips pierced through is a second layer called a slip layer, this is there to stop the screed getting between the insulation and lifting it up. 

 

You need to make it clear you you are not using block n beam but beam with insulation panels. 

 

What detail has the insulation block manufacturer recomended. 

 

And why use the insert insulation if it’s £3000 dearer than normal blocks. 

Makes no difference. I understood it. The dpm is underneath. The slip layer is on top.

I'm probably not going to use the beam and insulation, as it s that much dearer. It always seemed the more sensible idea as it eliminates an extra step (laying blocks), but  it s not such a good idea if the price difference is 3k.  I'm aiming for a mixture now, using minimal insulation in between the beams (as of jetfloor,beamshield....) and finishing off with regular insulation from seconds&co on top. So basically treating it like a block and beam floor.

think this should work

Edited November 3, 2019 by Patrick

[Oz07]

Wasn't it @Jeremy Harris who did some kind of test on the absorbancy and uptake of moisture of building products. For instance if the insulation was directly ontop of damp ground with dpm over top and staples through would moisture actually come up through the dpm. While I wouldn't advise it it's probably unlikely. When I asked about it previously someone else said the staples are tight around the dpm they puncture so ok

[bissoejosh]

5 hours ago, Patrick said:

Makes no difference. I understood it. The dpm is underneath. The slip layer is on top.

I'm probably not going to use the beam and insulation, as it s that much dearer. It always seemed the more sensible idea as it eliminates an extra step (laying blocks), but  it s not such a good idea if the price difference is 3k.  I'm aiming for a mixture now, using minimal insulation in between the beams (as of jetfloor,beamshield....) and finishing off with regular insulation from seconds&co on top. So basically treating it like a block and beam floor.

think this should work

 

I wanted to use the insulated beam and block but the cost simply didn't stack up. In the end I laid normal 7n blocks and got 150mm of Kingspan K103 from seconds and co for £24 a sheet. 

 

The stuff turned up brand new, still shrink wrapped with a few damaged corners on several sheets - bargain really.