Jump to content

Ground floor Nudura buildup and pour



We left you with a poured slab and we were chomping at the bit to get the ground floor Nudura walls up before the end of the year. Well, I am glad to report we got there - almost ? 


After getting the slab done, I figured I'd get ahead a bit and it would be a good idea to talk to someone about the waterproofing we would have to put on the outside the walls before we started backfilling. To cut a long story short

  • using waterproof concrete in walls such as these is a complete non-starter, so Type-B waterproofing cannot be used.
  • Visqueen's R400 Radon barrier is not an effective waterproofing method

and so we now face having to use a Type A and a Type C waterproofing method - basically this will mean for us a waterproof screed being added to the floor with channel ducting where the walls meet the floor and the "egg-crate" plastic material across the screed and up the inside of the walls. That should eat into our contingency ? ? ?


20211116_084212.thumb.jpg.849341bc58ae8524d394800470947ef3.jpg  But also it meant a dash to get some waterproof slurry to paint round where the Nudura blocks would be laid the following morning and mixing and painting it on under floodlights (it's the dark grey stuff in the picture to the right). Oh what fun!!



But, the following day we were up early to welcome out walls, the bracing and two fine chaps (Louie and Harry) from The Fell Partnership who would be helping us Day 1 to get the first row in place. We then scurried around unloading things off trailers and flat beds, and installing the waterbar between those pieces of upright rebar. By 10am we were ready to go.


By about 2pm we had most of the first row in and part of the second row (see below). If it hadn't been for some non-standard corners in the design, we would probably have been at Row 3, but that's what you get for following a design religiously ✝️


20211116_133958.thumb.jpg.65ef6fe04d93894fa7a14731a95419f0.jpg      IMG-20211116-WA0003.thumb.jpg.3d9cf1f6f43c2560f4f65ef169f712b9.jpg


(FYI - the T-corner is all to do with the design - don't ask yet)


On the second day we were left to our own devices, I had to make a dash to collect some extra Nudura parts and some waterproofing equipment (due to the direction our waterproofing system now had to take) so we made a later start but still we were very pleased to get up to 4 rows installed.

Day 3 we were ready to begin installing all the bracing system, and after hitting her head SWMBO was made to wear the Christmas present from her children.


20211118_112516.thumb.jpg.e48a8418fa02f6e617c2addc24b131fe.jpg   20211119_071043.thumb.jpg.5b251464aab9eb34a97e27240b75078c.jpg


and on Day 4 it inevitably rained in Cornwall ? , but before our help arrived again we had managed to just squeeze a block on to Row 6 (the final row before the first pour of concrete)


After the help on Day 4, we continued to finish things off on Day 5 by constructing part of an internal load bearing wall, and a wall with the only window opening at this level which will be for the family bathroom. FYI - the rest of that side of the house will consist mainly of windows into bedrooms plus some extra small sections of walling (to be determined)




 Where we were not able to complete things before the pour happened (time didn't allow) was where the internal wall meets the external wall and there are two doorways to construct (this is why I said we almost made it). I will have to do these in the New Year, mixing and pouring the concrete by hand (just under 1 cubic m) so that'll burn off the Christmas pudding ?


A week later (during which we had some more high winds) I came back down to finalise a few bits (like lack of scaffold planks and bracing in some places) to be greeted by a snaky ?  wall.






so that was all straightened up, the rest of the bracing fitted, and the Nudura joist hangers inserted. 20211128_115557.thumb.jpg.159f319ae839cf3d5c0d9a4983fd7bf9.jpg


(Between straightening and the pour we had Storm Barra, but my remedial work held up nicely)














I won't bore you with pictures of hunky men doing manly stuff with concrete pumps etc. but suffice to say it all went very well, with no leaks or blow outs so "he who shall not be named from Channel 4" would have been very disappointed if he was allowed onsite.


And so, last weekend (after a midweek pour in the remnants of Storm Barra) I was able to deconstruct the bracing and we are now the proud owners of some freestanding, high-wind-proof walls.























Really happy at the attention to detail that Louie and Harry paid to ensuring the walls were straight and true before the pour began - right up my street.


So now we have a tidyish site again (for a short while) ready for steels installation in the New Year. We have to finish off the internal wall, then waterproof and backfill outside, and install joists and flooring before we can continue with building the upper floor walls. We're hoping that by middle of next year we can start on those upper floor walls.


So until 2022, and the inevitable next lockdown, I wish you all a very Merry Christmas ? and a Happy New Year ?

  • Like 9


Recommended Comments

Looks great.


We used waterproof concrete with our polystyrene ICF walls - not Nudura. This is on top of the waterproof concrete raft coupled with a water bar placed into the raft. 


We backfilled part of our ground floor (built into a slope) but clad the ICF walls using heavy concrete blocks which were then coated in a tanking slurry. Seemed like overkill to me but that's structural engineers for you.

Link to comment
17 hours ago, Happy Valley said:

Seemed like overkill to me

I think it all depends on which "professional" you speak to as to what they want. ?


Link to comment
9 hours ago, freshy said:

@BotusBuild How did you put up your bracing without hitting the UFH pipes in the concrete?

*copied from an earlier post. 

We have now passed this phase of our build, the ground floor walls pour has been completed. In the end the UFH pipes were cable tied to the top of the reinforcement mesh in the middle of the raft. The raft was 150mm thick, the top of the UFH pipe in most places was at 80mm, with 70mm of clearance from the top surface. In some areas where there was 50mm ducting for water pipe runs, the reinforcement mesh was lifted and the UFH pipes were at 110mm with only 40mm of clearance. 

The wall props were 114cm long, and placed 120cm apart with fixings at 18cm and 1m. For the front fixing the builder used M10x70mm tapcon style bolts, we had no UFH pipe where there were front bolts fixings. For the rear bolt fixings we used M8x50mm tapcons, there was UFH pipe present for all these fixings.


We ran an air pressure test during the prop fixing process and none of the UFH pipe work were compromised. The walls were poured with only one very minor incident and the props have now been taken down. Hopefully this helps anyone that is concerned with how ICF wall props work when you have an insulated raft with UFH.

  • Thanks 1
Link to comment
On 24/10/2022 at 23:31, freshy said:

How did you put up your bracing without hitting the UFH pipes in the concrete?

Scaffold planks on the slab, held down with lots of high density concrete blocks although some very high winds moved even those prior to the pour day.

We did use dome shorter (40mm) concrete screws with an extra washer or two in places as well.

Link to comment

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Create New...