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Insulating a beam and block floor


dnb
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I have a site with lots of oak trees on high shrinkage potential clay, so I have opted for a pile and ring beam foundation with a beam and block floor. I seriously looked at a passive slab, but the costs associated were prohibitive and there's very expertiese here for such schemes.

 

I am seeking to achieve a very good level of insulation - my target for the floor is a U value of 0.1m/m^2. If I use traditional beam and block with 150mm of kingspan on the top I can achieve this.

 

I then looked at a scheme called "Tetris", that promised a very insulated floor, dispensing with the blocks. (There are loads of this sort of product, this is just one example.) I looked at the specs and found that if I used Tetris it would sit 150mm above the beams (the same as the Kingspan) but only achieve a U value of 0.2w/m^2. So near double the thickness and half the insulation. I could get to 0.13w/m^2 by 75mm of additional insulation but why would I choose this over the simple traditional method?

 

Am I reading the specs right? It doesn't seem right somehow - where is the advantage in the new method, other than not having to lift loads of concrete blocks?

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Big developers near me using one of these systems on a nearby job. Suspect they like to choose a system and stick with it. As has been said different insulation used. I used 6" PIR on last job under floor and don't think I hit that u vale, more like .15 from memory?

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I think you need to look at the whole system costs. To get to 0.13 by standard construction you will need 160mm of PIR over the slab, plus the screed at 75mm.  Whilst Tetris will be an additional 85mm in height, it’s cost saving is that you don’t need the block infill as that is replaced with the EPS, and your PIR cost will be lower. 

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6 minutes ago, PeterW said:

I think you need to look at the whole system costs. To get to 0.13 by standard construction you will need 160mm of PIR over the slab, plus the screed at 75mm.  Whilst Tetris will be an additional 85mm in height, it’s cost saving is that you don’t need the block infill as that is replaced with the EPS, and your PIR cost will be lower

 

 

Agreed to that, I had a look at all these systems as well and found springvale beamshield very clever. The insulation sits in between the Beams and not just on top. With beamshield it also has a layer underneath the beams, so you are getting a thicker insulation without raising the total  floor level. Problem I have with them, can't get a quote out of them. Been trying for 6 months now chasing after them. A nightmare to deal with. Tetris was alright and quote came In reasonable, but the system is not that superior over just putting Kingspan on top. Like you said. I stayed away from Jetfloor as their quote was rather high (60% higher than Tetris), but maybe that will be different in your case.

 

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Another point to consider is that a fancy insulation system dictates a floor finishing schedule which might not be convenient for the overall build plan.

 

A standard block floor can cope with 6 months of building traffic as the main structure is erected. Once the roof is on and the building is weather tight and frost proof, then the UFH, insulation and finishing screed can be installed without weather concerns.

 

The recent grand designs series illustrated the problem when that poor retired lady encountered all sorts of delays which resulted in her concrete floor cracking open due to frost damage. There were open window and door apertures which might not have been a concern when the floor was installed in the summer. I assume the water used to pressure test the UFH was left and then ultimately froze. 

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  • 3 weeks later...

Hi, we are having to put a steel ring beam in due to flood risk. Our neighbours are currently building a timber house and their floor is approx 1 metre above ground level. They used wood joists and chipboard floor. The building inspector said it was a fire risk due to the gap between ground and floor and made them put 2 layers of fireboard under the chipboard.

They said it was very difficult as they had under a metre of room to work with and it was a back braking job, the Tetris system may therefore may need fire protection, I have tried to get information as to the options we can use but it is a bit of chicken and egg as I cannot get an inspector to help without first producing drawings and I am trying to find the solution and then have drawing produced.

 

So be careful if there is a gap between ground and floor as to the type of material that can be used.

 

Regards

Colin

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  • 10 months later...

Thanks for the 

On 10/07/2019 at 07:52, Patrick said:

 

Agreed to that, I had a look at all these systems as well and found springvale beamshield very clever. The insulation sits in between the Beams and not just on top. With beamshield it also has a layer underneath the beams, so you are getting a thicker insulation without raising the total  floor level. Problem I have with them, can't get a quote out of them. Been trying for 6 months now chasing after them. A nightmare to deal with. Tetris was alright and quote came In reasonable, but the system is not that superior over just putting Kingspan on top. Like you said. I stayed away from Jetfloor as their quote was rather high (60% higher than Tetris), but maybe that will be different in your case.

 

 

I'm looking for insulating beam/block, also found this similar system to Beamshield:

 

https://www.cemex.co.uk/readytherm-insulated-concrete-floors

 

@epsilonGreedy the point about traffic on floors is very valid. It's a shame someone doesn't do a concrete block with insulation bonded underneath.

 

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We have the Jetfloor system. Funny thing is it was about 15% cheaper than Tetris when we had our quotes (about 5 years ago). Makes you wonder sometimes whether someone just sticks a finger in the air on prices.

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  • 1 month later...
On 10/07/2019 at 07:52, Patrick said:

 

Agreed to that, I had a look at all these systems as well and found springvale beamshield very clever. The insulation sits in between the Beams and not just on top. With beamshield it also has a layer underneath the beams, so you are getting a thicker insulation without raising the total  floor level. Problem I have with them, can't get a quote out of them. Been trying for 6 months now chasing after them. A nightmare to deal with. Tetris was alright and quote came In reasonable, but the system is not that superior over just putting Kingspan on top. Like you said. I stayed away from Jetfloor as their quote was rather high (60% higher than Tetris), but maybe that will be different in your case.

 

FYI I persevered with Beamshield, and finally got a price after about 5 weeks. They wouldn't quote direct for the insulation, but instead asked me to get a quote via a local beam casting company that they dealt with. The price on a 60m2 floor using the Beamshield Plus product (all insulation between/underneath the beams) for a U-value of 0.13 didn't seem too bad given the benefits in construction speed, just a tad over £40/m2 delivered excluding the topping.

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30 minutes ago, Reiver said:

FYI I persevered with Beamshield, and finally got a price after about 5 weeks. They wouldn't quote direct for the insulation, but instead asked me to get a quote via a local beam casting company that they dealt with. The price on a 60m2 floor using the Beamshield Plus product (all insulation between/underneath the beams) for a U-value of 0.13 didn't seem too bad given the benefits in construction speed, just a tad over £40/m2 delivered excluding the topping.

 

We used Charcon four years ago to supply and fit Beamshield.  £17,334 to do about 357m2, so just under £50 per metre.  Included crane.  We did the concrete topping.

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  • 1 year later...

Blowing the dust off this one.

 

Would anyone NOT go for Beamshield instead of a traditional block and beam solution? The Beamshield just seems an utter no-brainer from where I'm sitting. The thought of a constant cold ventilated setup just doesn't bode well with me, particularly when the time you're heating it is when the cold air will be in abundance AND Baltic cold to boot.

 

Any Nay-sayers out there? And if so, why?

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Beamshield requires void underneath, as it is beam&block system, just EPS block. The greatest drawback is need for protection from damage during further stages of the build. From other practical issues it may be the supply: finding local casting company that collaborates with them (though there are similar alternative systems), volume required (whole house is more likely to succeed, my extension failed to fill an artic) and competition from volume builders if present around (one of the companies I talked with at some stage pulled out, as their whole output was sucked by major developer).

But in principle yes, it's a no brainer. Though so is single skin externally insulated wall as used throughout Europe, yet cavity rules :)

 

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I used the Floorspan Efloor Plus - similar approach I think with EPS blocks and a 150mm EPS sheet over the top.

 

Good system.

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2 hours ago, Faz said:

I used the Floorspan Efloor Plus - similar approach I think with EPS blocks and a 150mm EPS sheet over the top.

 

Good system.

Yup, many thanks for this. Like the Beamshield but they ( BS ) beef up by going underslung as well which I really like the idea of, vs the 150 that these guys go for on top. Could go to a 100mm PIR atop if DPC / FFL heights becomes an issue I suppose.

More options are always welcome, cheers :) 

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  • 2 weeks later...

I have literally just commissioned Jetfloor for our 0.15u Value build. Complete supply kit with beams and the insulation for £4.4k @ 98sq m. 

 

It was more cost effective than Tetris, and £150 more than Millbank (but they would only achieve 0.16u with the similar buildup).

 

 

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13 minutes ago, BartW said:

I have literally just commissioned Jetfloor for our 0.15u Value build. Complete supply kit with beams and the insulation for £4.4k @ 98sq m. 

 

It was more cost effective than Tetris, and £150 more than Millbank (but they would only achieve 0.16u with the similar buildup).

 

 

That sounds like a good price given recent cost increases as it's only about £150 more than we paid for 123m2 circa six years ago.

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16 minutes ago, NSS said:

That sounds like a good price given recent cost increases as it's only about £150 more than we paid for 123m2 circa six years ago.

 

Had I pulled a finger out 12 months ago, this quote would have been just under £3.5k ...

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6 minutes ago, BartW said:

 

Had I pulled a finger out 12 months ago, this quote would have been just under £3.5k ...

It was a Hanson product back when I used it, but I heard it's no longer in their stable?

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22 hours ago, NSS said:

It was a Hanson product back when I used it, but I heard it's no longer in their stable?

All I know is they brand it as Bison System by Forterra. The beams that is. 
 

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15 hours ago, BartW said:

All I know is they brand it as Bison System by Forterra. The beams that is. 
 

Yep, that's the stuff 👍🏻 

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Maybe HX Plus for use beneath reinforced concrete floor slabs to protect against the potential effects of ground heave...

365mm HX Plus is a combination of 215mm Cellcore HX S Under Slab EPS bonded to 148mm Filcor EPS100 and protected by an ultra thin 2mm twin fluted polypropylene sheet on the top which is strong enough to actually walk on during installation.

365mm Cellcore HX Plus thermal resistance is 4.17m2c/w based on the 148mm Filcor EPS100 insulation layer incorporated within the panel.

https://cordek.com/products/cellcore-hx-plus

https://cordek.com/uploads/standard_details/ground_heave_sd_cellcore_plus_high_heave.pdf

https://insulationgo.co.uk/365mm-hx-plus-cellcore-under-concrete-floor-slab-eps-insulation-board-insulated-heave-protection-grade-9-13/

https://insulationgo.co.uk/blog/cellcore-hx-s-plus-insulated-void-formers-eps/

 

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