Beam and block floor and integrated EPS insulation (e.g. warm beam))

[Moonshine]

On various searches and review of construction methods, i think that i would do a block and beam floor between a basement and ground floor, and as a standard ground floor.

 

I have come across EPS blocks that form an insulation layer as part of the beam and block construction as below;

 

Has anyone come across this type of product before as if it isn't too expensive, it seems like it would be a good solution of saving space, costs, and labour of not having to manual handle 100's of blocks in the floor.

[bassanclan]

Lots of similar systems, tetris, Hanson jet floor etc. You really want a layer of insulation over the beams in addition to what is shown on the diagram.

 

Check u values and prices, but also beam deflection if you are having spans over 4m especially 

[jamiehamy]

We used Tetris. Avoided having to carry thousands of blocks up the hill and fitting them. Nice thermal bridge free joinds with the ICf walls as well. Very easy to do. 

[Moonshine]

23 minutes ago, bassanclan said:

Lots of similar systems, tetris, Hanson jet floor etc. You really want a layer of insulation over the beams in addition to what is shown on the diagram.

 

Check u values and prices, but also beam deflection if you are having spans over 4m especially 

 

Thanks, from the drawings i think that the longest span is about 4.4m, so may need to put a dwarf wall in the middle of that span (its not over the basement area).

 

@jamiehamy Do you know where i can get an idea of costs from, as i would be interested to see who it stacks up

Edited January 20, 2020 by Moonshine

[jamiehamy]

13 minutes ago, Moonshine said:

 

Thanks, from the drawings i think that the longest span is about 4.4m, so may need to put a dwarf wall in the middle of that span (its not over the basement area).

 

@jamiehamy Do you know where i can get an idea of costs from, as i would be interested to see who it stacks up

I'll have a dig around when I get home. I'll have our actuals that I can send you (although we had 5 and 5.5m spans). Spantherm and Jetfloor wouldn't quote. Tetris made a cockup by not reading the requirements right  but massively to their credit, they did everything they could to get us a working design. They went over and above when they could quite easily have said 'can't be done'. 

 

 

[NSS]

We have Jetfloor. Our longest spans are 4.45m and they had no issue with that.

 

Total cost (supply only) for all materials (123m2) was £4,550 (albeit that was in 2015).

 

Included 57 beams, infill books, inlay sheet, overlay sheet, Thermalite beam end spacer blocks, Thermalite edge blocks and Thermalite coursing blocks (for top of dwarf walls).

 

We also had perimeter blocks to insulate the slab from the external walls and have Perinsul glass blocks in the below DPC build up of the external 'skin' to minimise cold bridge to the timber frame.

[jamiehamy]

For around 210m2 of 150mm insulation and 5 and 5.5m beams, we were £55m2 exc VAT. The long beams added a lot, but as the sleeper walls were down we had to go with that. So that was beams, closer blocks, insulation and gap strips - delivered to Scotland.

 

It's a super easy system to install - I'd use it again for sure. 

[Oz07]

They're probably not bad value when you take insulation into account. Blocks would be a tenner a m2, beams normally 15 20 ish? From rough memory 

[Russell griffiths]

Is your basement heated or unheated, if it’s heated then I cannot see why you need an insulated floor. 

If unheated then yes I can. 

I believe @Patrick has just looked into this and the pre formed insulation blocks are very expensive, so he is thinking of making his own from 100mm eps sheet. 

[Moonshine]

21 minutes ago, Russell griffiths said:

Is your basement heated or unheated, if it’s heated then I cannot see why you need an insulated floor. 

If unheated then yes I can. 

I believe @Patrick has just looked into this and the pre formed insulation blocks are very expensive, so he is thinking of making his own from 100mm eps sheet. 

 

The garage part of the basement is unheated so it's needed above there. The other area of the basement is the entrance lobby / atrium, and probably won't need b&b there, probably a small section of timber floor as it is a void above to the main part.

@Patrick I would be interested to know what you ended up finding out, and if you where planning to shape them to the beams, e.g. the bottom 50mm would need to be cut in by approx 15mm either side, labour intensive, but could be quick with a circular saw with a good blade to cut the eps (would need to think how to minimise tear out / foam dust.

Edited January 21, 2020 by Moonshine

[Patrick]

@Moonshine

I am doing Insulated block and beam and tried forever and a day to buy insulation only (the blocks that are "t-shaped" in order to fit them).

Nobody is selling them on itself. Only the whole floor system, and then they have a markup on every item involved, which ends up approx 70-80% more expensive than a traditional block and beam with cheap insulation on top (what @Russell griffiths

Is doing)

Insulation is the most expensive bit in this calculation so it matters where you get it from. The companies that do the floorsystems (jet floor, beamshield, Tetris,...)

Charge a premium on top of regular eps prices which isn't little.

I didn't start yet, but I am thinking of doing exactly as you mentioned. Get the board cheap from either seconds and Co or from a eps supplier and cut them to size.

Yes-I expect this to be labour intensive and certainly buying the ready floor is quicker. It s just a matter of how much you normally earn in your day job and if you rather make that money doing overtime or if you spend it on your house - it obviously makes no sense saving 1000£ on material and spending 5 days of work if you are an architect ?

You rather work an hour to make that extra grand.

 

I will keep you updated with the progress.

 

 

Edited January 21, 2020 by Patrick

[Moonshine]

I have just look a little at foam cutters and there are some DIY heated element cutters powered by a car battery.

Potentially as long as you use a source with enough amps you could hear up a piece of wire at right angles to cut the recess.

The issue would be the wire being firm enough to keep its shape but also thin enough to have high resistance for the heat. I guess you could use a metal angle behind the cutting element for rigidity.

Worth some testing if the costs are as high as you say they are.

The sections could be cut in free time before the build

[Patrick]

I will test it out. I went down the labour intensive route with every step so far. Some did save a bit of money, some came out the same price. All together still savings to be made. Unless you calculate your own work, but just look at everybody on this forum, houses wouldn't be built and budgets could have never been kept without the time and efforts you put into the building yourself.

 

In case you haven't seen it yet, different topic discussions about the block and beam insulation

 

Edited January 21, 2020 by Patrick

[Moonshine]

11 minutes ago, Patrick said:

I will test it out. I went down the labour intensive route with every step so far. Some did save a bit of money, some came out the same price. All together still savings to be made. Unless you calculate your own work, but just look at everybody on this forum, houses wouldn't be built and budgets could have never been kept without the time and efforts you put into the building yourself.

 

In case you haven't seen it yet, different topic discussions about the block and beam insulation

 

If it was something that i could do outside my 9-5 i would put it in the 'free' category.

 

I hadn't seen that thread, and to get round the 'T' shape issue i like the use of two thicknesses (100mm and 50mm) however i would probably think some sort of mechanical fixing (plastic) would be needed rather than just glue.

[Russell griffiths]

7 hours ago, Moonshine said:

 

If it was something that i could do outside my 9-5 i would put it in the 'free' category.

 

I hadn't seen that thread, and to get round the 'T' shape issue i like the use of two thicknesses (100mm and 50mm) however i would probably think some sort of mechanical fixing (plastic) would be needed rather than just glue.

Nope glue only, try sticking to sheets of eps together and then pulling them apart, you will tear chunks from the eps before you separate the join. 

[Oz07]

Isn't the important thing getting a certified floor system with bba cert? Doubt homemade eps would qualify

[Judy C]

We have just installed an insulated beam floor - our's was by Lynx Precast.  All went very well.  The build up was 150mm beams with T shaped blocks between, dpm, 135mm EPS on top - this was supplied with a polythene sheet glued to the top to make it easier to clip the u/floor heating pipes to it, 30mm EPS to perimeter, 90mm reinforced concrete slab to be poured to dpc level as soon as there are 48 hours without rain forecast.  The EPS is graphite enhanced so that we are getting a U value of 0.12.  

[Oz07]

Are you having a warranty? Is it right that nhbc make you have mesh in beam and block like this now?

What's the u value?

Did you find cheaper than standard b&b

[Judy C]

It wasn't cheap but you can get more of the cheaper insulation in this way.  So if I had gone for standard beam and block floor, I would have had to use something like 225mm Kingspan to achieve a U value of 0.12 - would cost several thousand over this area.  It was interesting to work with - builder hadn't come across it before - and was a problem when the blocks started blowing away in one of the storms!

 

Also this way round the finished slab will be in place before the frame goes up.  So will be perfectly dry by the time the floor finishes go in.

 

The mesh is just to make it easier to clip the pipes to, and when taped stops the concrete falling into any cracks.  No need for a polythene separating layer as with Kingspan as concrete doesn't react to EPS.

 

We are having a warranty (Protek) - no issues with this.

[Moonshine]

1 hour ago, Judy C said:

It wasn't cheap but you can get more of the cheaper insulation in this way.  So if I had gone for standard beam and block floor, I would have had to use something like 225mm Kingspan to achieve a U value of 0.12 - would cost several thousand over this area.  It was interesting to work with - builder hadn't come across it before - and was a problem when the blocks started blowing away in one of the storms!

 

Are you able to share the costings of the Lynx Precast, or either the £/m2 for the beams and inserts?

 

I have gone away from the insert method, based on a discussion i have with a suppler, but a real world example would be very interesing.

 

Where did you get the figure of the 225mm from (what kingspan product was it)? as the online calculator indicates U value of 0.11 with 150mm of Kingspan Kooltherm K103

 

https://www.uvalue-calculator.co.uk/calculator/floors/ground floor/beam and block (insulation below screed)/1/150/

 

Though 150mm of Kingspan Kooltherm K10 is about £50-55 m2 material only.

Edited March 4, 2020 by Moonshine

[Judy C]

It was about £40/sqm to supply for the graphite enhanced EPS (150mm between the beams, 135mm above with grid attached for heating pipes) , infill blocks, perimeter insulation.  We had it fitted by them (just the beams and the infill blocks) which they did in a day and brought their own crane, cost about £1k extra.  The 135mm was supplied because we have heating pipes and therefore need a reinforced concrete topping of 90mm (minimum is 75mm above any pipes)

 

I am probably misremembering - it would have been 150mm of Kingspan.  

[Oz07]

Does to £40m2 inc beams or just insulation. Where is your dpm if no polythene. Also I meant steel mesh in concrete, do you need this?

Thanks for the detail very interesting. 

[Judy C]

Included beams and all the insulation - this depends on what U value you want to achieve.  

 

The dpm is between the first layer of insulation (ie the t shaped pieces between the beams) and the second layer of insulation, then brought up to dpc level at the slpper walls and around the perimeter.

 

The mesh in the concrete is because this is the main structural slab.  Lynx provide the specification - I think there are alternatives if you look at their literature.

 

 

[Moonshine]

30 minutes ago, Judy C said:

Included beams and all the insulation - this depends on what U value you want to achieve.

 

That's are really good price (installed?), what was the total m2 area?

 

i have had a quote £1k for just the supply of beams for about 70m2. Assume a block area of 0.1m2 each and a block floor area of 60% total, that is ~420 blocks, another £400.

 

if using 150mm of Kingspan Kooltherm K10 at about £50 m2 material only, thats another £3,5k.

 

In total that is £5k in materials only, and probably another £1.5k in labour.

 

So if i could get any thing like £40/m2 installed (in the south west), i would take that as its circa £3k!