UFH pipes protection/testing/fluid in slab.

[SuperJohnG]

Nearly there with starting the foundations for my insulated raft foundation, just sorting out the nuts and bolts and getting prepped for installing the UFH pipework, to be supplied by Wunda. 

 

My Pipework is to go in the slab which is 250mm ringbeam with 150mm main section. I will be installing the month, and hence it'll be cold and likely freezing temps for some time yet. I have the design now I just have a few questions if anyone can provide some input:

 

 

1) Most with insulated foundation seem to attached pipes to mesh with cable ties or similar. However Kore (foundation supplier) seems to mention that they should be installed first before mesh to keep them protected (makes sense) see image at bottom. Hence stapled into the EPS and out the way. Seems like the best plan (and a lot easier to fit not walking on mesh) probably two questions here: 

        1a) Is there any good reason others fit it to the mesh? rather than then EPS?

        1b) Will it matter with pipes being that 'deep' in the slab?. Heat rises obviously, but it the only down side that the reaction time takes longer than say being on mesh at half the depth of slab? (I.e.                   150mm deep vs 75mm deep)

 

2) Should I get manifold just now or just cap ends and leave attached to wooden support. (saves manifold getting damaged?)

 

3) How best to test the pipe integrity once installed? any good links to hand pumps/ gauges? (Manifold might be helpful here)

 

4) Should I leave pipes filled while doing the concrete pour? I have seen others say we should/ others that haven't. Does it really matter? 

 

5) If I did leave fluid in the pipes for pour, should I use anti freeze in order or avoid any freezing issues and pipe damage following the days the concrete is curing?

 

6) Any other hints / tips? 

 

 

 

 

 

 

 

 

[LA3222]

1. I attached mine to the top of the mesh, the thing i didn't like about it is where you have mesh laps it means your pipes are even higher and so less cover. I seem to recall thinking that putting the pipes onto the insulation first would be better.

 

2. I'd get the manifold.  Position it where it will go, but higher so you have excess pupe allowing you to adjust once house is up. Better to have too much pipe. Also allows you to pressure test. I just wrapped some foam around mine during the pour.

 

3. Manifold and fill with water from a hose.

 

4. I did. The pressure will go up as concrete cures but you get the warm and fuzzy that they aren't leaking. Just dont let pressure go too high like I did....came out in the morning so see zero bar, took a couple of mins to realise the needle had gone right around and broken the pressure gauge.

 

5. I did mine same time of year as you and didn't use anti freeze, maybe should though as may freeze so not worth risk.

 

6. Spray paint on EPS isn't good - melts it. I was going to mark out walls etc. In the end I used wooden battens to show where walls were and cut out pieces to show location of doors.

 

7. I used cable ties to mesh. PITA as you get through thousands so takes a while and then have to snip ends off. Dont do it. Stapling to EPS get a stapler in for in, if tying to mesh use the same twist wires as you use to tie mesh.

 

Hire a wire tie gun when doing the mesh, and then you can use it to tie the pipes too.

 

Don't tie mesh together by hand, I did, its not hard just bloody slow.

 

You can get a gun that does it for you, try and hire one of those.

 

Doing your founds is easy bud, I'd say the key is try and make aspects of it easier for yourself if you can. Lazer level, wire tying gun etc are the sorts of things which can make things go easier for you.

Edited January 6, 2021 by LA3222

[willbish]

I took a different approach

 

1a Certainly easier if you csn staple to the EPS. I cable tied to the top of the mesh. Are you putting a thin layer of DPC to stop any concrete seepage between the EPS joins?

1b No I don't think it matters at all. Over time, the slab will be heated to a uniform temp regardless of the position of the pipes. I imagine some vertical variation in slab temp will occur when cooling down. It could be advantageous to have the pipes lower down, Im not sure.

 

2 I capped the ends  

 

3 I didn't test prior to pour. Pex-Al-Pex is surprisingly rigid. I think the only conceivable way of a puncture is sabotage. I was concerned with having people walk on the pipe during concrete placement, but it didn't flatten them.

If you do decide to pressure up the pipes, are you going to have someone watching the gauge during concrete placement? What are you going to do if mid-pour you notice the pressure has dropped? 

 

4 Leave them empty, forget about them 

5

6 If cable tying, no need to snip the ends off as well. Just rotate the tie as you are pulling tight and have the excess pointing down. Cable tying is certainly time consuming but it definitely works.

 

 

 

 

[SuperJohnG]

2 hours ago, LA3222 said:

2. I'd get the manifold.  Position it where it will go, but higher so you have excess pupe allowing you to adjust once house is up. Better to have too much pipe. Also allows you to pressure test. I just wrapped some foam around mine during the pour.

Thanks. I just hadn't figured out the IVAR manifold yet or the Wunda one. (IVAR website seems a pain and too many options) 

 

2 hours ago, LA3222 said:

 

3. Manifold and fill with water from a hose.

Only issue here is I will have no running water on site then, but can maybe just get a wee pump and take some water up. 

 

2 hours ago, LA3222 said:

Doing your founds is easy bud, I'd say the key is try and make aspects of it easier for yourself if you can. Lazer level, wire tying gun etc are the sorts of things which can make things go easier for you.

Thanks all helpful wee bits. 

 

1 hour ago, willbish said:

I took a different approach

 

1a Certainly easier if you csn staple to the EPS. I cable tied to the top of the mesh. Are you putting a thin layer of DPC to stop any concrete seepage between the EPS joins?

1b No I don't think it matters at all. Over time, the slab will be heated to a uniform temp regardless of the position of the pipes. I imagine some vertical variation in slab temp will occur when cooling down. It could be advantageous to have the pipes lower down, Im not sure.

 

2 I capped the ends  

 

3 I didn't test prior to pour. Pex-Al-Pex is surprisingly rigid. I think the only conceivable way of a puncture is sabotage. I was concerned with having people walk on the pipe during concrete placement, but it didn't flatten them.

If you do decide to pressure up the pipes, are you going to have someone watching the gauge during concrete placement? What are you going to do if mid-pour you notice the pressure has dropped? 

 

4 Leave them empty, forget about them 

 

The stapler defo seems like the easier option from here. No DPC on mine (drgs anyway) it goes below mine, which seemed easier. It seems a pain and extra step I could avoid there, also it meant it I had the foundation sitting without doing pour for a few weeks then it wouldn't fill with water as much. Does it seep a lot? 

 

Defo makes sense on maybe leaving water out at concrete pour and there is nothing you could do at that point. I'll maybe test prior to pour, to give me confidence it's not damaged then pump water out using air to avoid any overpressure or freezing issues. 

[willbish]

16 minutes ago, SuperJohnG said:

Does it seep a lot? 

I'm not familiar with the Kore system, are the boards interlocking? There's potential for a bit of seepage with gaps and a wet pump mix. A thin DPM would prevent this but it's extra time and cost especially if you start getting the internal corners cut and taped nicely.

 

I'd question the usefulness of filing and emptying the UFH pipes, particularly if you haven't got a mains water connection. That sounds like hassle.

 

There's always a chance if you pump out prior to pouring, potentially damage could happen between then and pour day. It's a risk but very minimal. 

I'd trust the pipe, you are buying from a reputable company, it won't be full of holes!

 

[JFDIY]

Benefit of pressurising them is that you proove them once fitted, but also stops them collapsing  when walked upon, and people will step on them regardless of how careful you expect them to be.

 

They won't freeze while the slab is curing due to thermal rise in concrete. If you want to drain them once concrete will bare your weight (a few days) you could blow them out with compressed air.

[LA3222]

2 hours ago, willbish said:

What are you going to do if mid-pour you notice the pressure has dropped

Excellent point, you're committed here, you can't stop so it makes no difference. Its probably the fact you can give yourself confidence prepour all good, but that doesn't preclude an issue happening mid pour you can do nothing about.

 

They are pretty solid pipes, I walked all over mine and so did the concreters?‍♂️

1 hour ago, SuperJohnG said:

Thanks. I just hadn't figured out the IVAR manifold yet or the Wunda one. (IVAR website seems a pain and too many options) 

I have the wunda manifold and my ivar pumpset arrived about 15mins ago. I assume that the two will go together, may involve the purchase of some additional couplers. I intend to look at it this week at some point.

 

The kore joins will stagger themselves as you install it, dont worry about seepage, you may get a little at the top layer but it will be stopped by layer below it.

 

The insulation will fill with water regardless of if it has a dpc or not. If you don't need to put a dpc in then don't, corners are a pita, leave it underneath.

 

If it rains (before mesh etc goes in), just use a big broom to sleep majority of it to a corner and scoop it out. I found that a dustpan used like a shovel worked a treat. Dont worry about 'a bit' of water being in there for the pour, its fine.

 

A bit of rain tended to dry up fairly quickly in the raft pre pour.

[SuperJohnG]

1 hour ago, willbish said:

There's always a chance if you pump out prior to pouring, potentially damage could happen between then and pour day. It's a risk but very minimal. 

I'd trust the pipe, you are buying from a reputable company, it won't be full of holes!

Was more about it being walked on and damaged than arriving with holes. Once installed I'll pressure test (time allowing!) then blow out with compressed air I think. 

 

1 hour ago, LA3222 said:

I have the wunda manifold and my ivar pumpset arrived about 15mins ago. I assume that the two will go together, may involve the purchase of some additional couplers. I intend to look at it this week at some point.

Ah, I'd assumed it was an IVAR manifold with pump/blending set - this would make it less of a decision just now for me. @Nickfromwales any insight here you can provide please? Do you buy a full IVAR manifold and pump/ blending set or Wunda manifold with IVAR blending set?  

 

1 hour ago, LA3222 said:

The insulation will fill with water regardless of if it has a dpc or not. If you don't need to put a dpc in then don't, corners are a pita, leave it underneath.

 

The corners is exactly what I wanted to avoid - as I'd seen you other posts! Stuff it  - DPM underneath only, all about making life easy.  

[LA3222]

I checked a minute ago and it looks like they join together.

Edited January 6, 2021 by LA3222

[Nick Laslett]

My thoughts is to use air to pressurise the pipes, @Nickfromwales talks about this approach. Filling with water can be a hassle if you haven't got supply to the site, then there is an issue of an unexpected freezing spell.

 

I was going to attach the pipe ends to a plywood board using a couple of clip tracks. Then cut pipes and install manifold during first fix. There is a post here showing an upstand with steel legs connected to the plywood. 

Edited January 28, 2021 by Nick Laslett

[Nickfromwales]

On 28/01/2021 at 22:33, Nick Laslett said:

My thoughts is to use air to pressurise the pipes, @Nickfromwales talks about this approach. Filling with water can be a hassle if you haven't got supply to the site, then there is an issue of an unexpected freezing spell.

 

I was going to attach the pipe ends to a plywood board using a couple of clip tracks. Then cut pipes and install manifold during first fix. There is a post here showing an upstand with steel legs connected to the plywood. 

Iirc, the UFH pipes from Wunda come Pre-pressurised with air / gas and the ends plugged sealed and factory tight  judging by one I cut ( without knowing they’d started doing this, so subsequently nearly ? myself ), it’s at quite high pressure too. You’d 100% know you’d damaged it, but would the person who’s damaged it tell you? Also, a tiny puncture may not be notable so maybe not the immaculate solution. 
A pressure gauge is the only true way of knowing that the integrity has not been compromised. Water is not necessary, but it’s 500 times quicker to find a leak with water squirting out vs using leak detecting fluid with air. 

[SuperJohnG]

8 hours ago, Nickfromwales said:

Iirc, the UFH pipes from Wunda come Pre-pressurised with air / gas and the ends plugged sealed and factory tight  judging by one I cut ( without knowing they’d started doing this, so subsequently nearly ? myself ), it’s at quite high pressure too. You’d 100% know you’d damaged it, but would the person who’s damaged it tell you? Also, a tiny puncture may not be notable so maybe not the immaculate solution. 
A pressure gauge is the only true way of knowing that the integrity has not been compromised. Water is not necessary, but it’s 500 times quicker to find a leak with water squirting out vs using leak detecting fluid with air. 

@Nickfromwales they are (i received them the other day.)  And I was thinking the same...also in reality I'm the only one laying them. So I might fit them all. Then leave them capped and fit the manifold once all laid so hopefully o should be able to tell them are all OK.  I also bought the pressure gauge so will likely pressurise to check prior to concrete pour. 

 

 

[Nickfromwales]

Good idea. Only downfall is you have to have a bit more waste as you need a factory capped coil for every run. Having them 'gas' pressurised during installation and then pressurising with a gauge on the manifold prior to / during / after the concrete pour is the gold standard. You'll know if you had issues during installation as a damaged loop wouldn't give you the steam-train whooooosh when you cut each loop to fit the manifold.   

[SuperJohnG]

1 hour ago, Nickfromwales said:

Good idea. Only downfall is you have to have a bit more waste as you need a factory capped coil for every run. Having them 'gas' pressurised during installation and then pressurising with a gauge on the manifold prior to / during / after the concrete pour is the gold standard. You'll know if you had issues during installation as a damaged loop wouldn't give you the steam-train whooooosh when you cut each loop to fit the manifold.   

I have 11 loops, but 9 are 100m coils anyways so works out. so only two really to check at the end. 

 

For pressurising - have you done this by air / water? what the easiest way to connect up air to the manifold? would seem to be a pain either way. 

[Thorfun]

On 01/02/2021 at 09:28, SuperJohnG said:

I have 11 loops, but 9 are 100m coils anyways so works out. so only two really to check at the end. 

 

For pressurising - have you done this by air / water? what the easiest way to connect up air to the manifold? would seem to be a pain either way. 

Hi John, can you tell me how long it took you to lay your UFH? I have 680m of coils to fit this weekend before our slab pour monday/tuesday next week. was wondering if I could get it done in a day or if I should budget 2 days for it?

[SuperJohnG]

4 hours ago, Thorfun said:

Hi John, can you tell me how long it took you to lay your UFH? I have 680m of coils to fit this weekend before our slab pour monday/tuesday next week. was wondering if I could get it done in a day or if I should budget 2 days for it?

Took me probably 3 all in. Maybe could have done in 2 if I procrastinated less. I'd say 1 was a stretch for 680m pipe. Is it stapled down onto insulated foundation or fitted to mesh? Also do you have a decoiler? 

 

Make sure you check all the pipe lengths before laying if you have different loop lengths supplied! (See my blog post). 

 

[Thorfun]

2 minutes ago, SuperJohnG said:

Took me probably 3 all in. Maybe could have done in 2 if I procrastinated less. I'd say 1 was a stretch for 680m pipe. Is it stapled down onto insulated foundation or fitted to mesh? Also do you have a decoiler? 

thanks, good to know.

 

it will be cable tied to the mesh. I do have a decoiler and have watched some YouTube videos so think I should be ok. I'll give up my plans for Saturday and spend it laying pipe instead. then that'll give me the 2 days to do it in. hopefully it'll be enough!

 

4 minutes ago, SuperJohnG said:

Make sure you check all the pipe lengths before laying if you have different loop lengths supplied! (See my blog post). 

yeah, I remember reading that and have made a note to double check as I have one 80m coil and 6 x 100m coils.