GEOCELL foam glass for garage foundation?

[Russdl]

I don't know much about this GEOCELL foam glass gravel stuff but the more I look into it the more I think it will suit me just fine for my future garage/workshop.

 

It looks really straight forward. No trenches (but a deepish hole to dig). No EPS to cut. NO DPM it seems as well, and most of it I reckon I can do myself.

 

I'm sure there are catches that I'm unaware of (like price maybe?) what am I missing? Is this GEOCELL foam glass gravel a good option for a garage/workshop foundation?

 

 

 

[Adrian Walker]

Yes it is and I think it's great stuff.

[Russdl]

1 minute ago, Adrian Walker said:

Yes it is and I think it's great stuff

 

That's the kind of answer I was looking for 👍

 

What are the catches? I can't find any local supplier so I guess that's one.

[saveasteading]

Interesting stuff. Made from waste bottles. Stone that insulates.

No pir, no footings. What's not to like?

£130/m3 is a lot of course.

But how thick to insulate to standards and support the structure?

[Russdl]

4 minutes ago, saveasteading said:

Interesting stuff. Made from waste bottles. Stone that insulates.

No pir, no footings. What's not to like?

 

Exactly!

 

5 minutes ago, saveasteading said:

£130/m3 is a lot of course.

 

Exactly (again) plus, at this stage, I don't know what the delivery costs are likely to be. I'll try and find out tomorrow.

 

6 minutes ago, saveasteading said:

But how thick to insulate to standards and support the structure?

 

So far I've seen that 300mm is equivalent to 150mm PIR as far as the insulation goes and I think that 300mm would be a suitable depth for a garage foundation, but not confirmed yet.

 

[Adrian Walker]

7 minutes ago, Russdl said:

 

That's the kind of answer I was looking for 👍

 

What are the catches? I can't find any local supplier so I guess that's one.

 

Being recycled it could be cheaper. https://www.mikewye.co.uk/product/foam-glass-insulation-aggregate/. For a house the insulated slab the sheets have a slightly better spec. If you want a physical look I can drop the samples of Saturday morning?

[ADLIan]

Thermal conductivity of geocell is 0.08W/mK and for PUR 0.022W/mK so geocell needs to be almost 4 times thicker than PUR. Read the certificate very carefully as depending upon ground conditions a dpm will probably be required. Sheets of foamed glass are a very different product, expensive and not very pleasant to handle

[Russdl]

@Adrian Walker I'm going to give Mikewye a call in the morning and see what's what. (I'll PM re Saturday 👍)

 

@ADLIan Thanks for the info and will read the certificate numerous times until I finally understand it. Use of a DPM won't be a biggie but everything I've seen so far say's it doesn't need one as it's non wicking and water drains through it, I guess that's why it should be wrapped in geo textile so that it doesn't clog up?

 

9 minutes ago, ADLIan said:

Sheets of foamed glass are a very different product, expensive and not very pleasant to handle

 

I'm only interested in the Geocell gravel at this stage so won't be dealing with that stuff.

[Iceverge]

How about TLA? @Conor used it in his build. 

 

Professional — Energystore (energystoreltd.com)

 

 

[Adrian Walker]

15 minutes ago, Iceverge said:

How about TLA? @Conor used it in his build. 

 

Professional — Energystore (energystoreltd.com)

 

 

 

I don't think you can have it very thick, so the insulation benefit would be small IMHO.

[Russdl]

17 minutes ago, Iceverge said:

How about TLA?

 

Never heard of it (I thought TLA stood for 'Three Letter Abreviation") but after a quick look, isn't TLA just insulation whereas the Geocell gravel is the foundation, and insulation.

[George]

I've got 1.5m^3 spare in the West Midlands - yours for £100 (buyer to collect!)

[Russdl]

@George thanks for the offer but I’m not in the market yet. 
 

Any insight you can share from using it?

[Roger440]

Didnt use it for a workshop, but did in my house (old, no DPC etc etc)

 

Aside from cost, is little downside. I looked at it again for a workshop that would have the potential to flood, so definitely was in the running, as completely unaffected by water.

 

In the house, i used it for all the reasons they state, but inside the house, and not wanting to dig to far down and expose the foundations, its main benefit was being the load bearing AND insulating layer combined.

 

Of course, it doesnt meet current regs. Does your workshop need to?

[George]

1 hour ago, Russdl said:

@George thanks for the offer but I’m not in the market yet. 
 

Any insight you can share from using it?

Groundsworker was a bit sceptical but it's been there for three years with no issue. Floor is warm and no damp issues.

[Adrian Walker]

12 hours ago, Russdl said:

@George thanks for the offer but I’m not in the market yet. 
 

Any insight you can share from using it?

 

 

Details for foamed glass foundations attached.  

GEOCELL-Foundation-Details.pdf

[Russdl]

Thanks for that @Adrian Walker most useful (and I see the DPM does maker an appearance, no worries)

 

[Adrian Walker]

4 minutes ago, Russdl said:

Thanks for that @Adrian Walker most useful (and I see the DPM does maker an appearance, no worries)

 

 

To be honest with a garage you don't need a screed.

[Russdl]

14 minutes ago, Adrian Walker said:

To be honest with a garage you don't need a screed.

 

Spooky! That was my next question! (trawling through the Mikewye website now). 

 

My fermenting plan is to use the Geocell as per the image above, then build the garage/workshop in block off the raft, then use EWI to insulate the whole - questions seeking guidance regarding all that will be on their way in a separate post. (I've already been persuaded to go for UB steels for the roof)

[Russdl]

What floor U value should I be aiming for for a detached garage/workshop?

 

I can't find any guidance unless it's for a garage conversion, can someone point me to any guidance?

[BenP]

15 hours ago, Roger440 said:

Didnt use it for a workshop, but did in my house (old, no DPC etc etc)

 

Aside from cost, is little downside. I looked at it again for a workshop that would have the potential to flood, so definitely was in the running, as completely unaffected by water.

 

In the house, i used it for all the reasons they state, but inside the house, and not wanting to dig to far down and expose the foundations, its main benefit was being the load bearing AND insulating layer combined.

 

Of course, it doesnt meet current regs. Does your workshop need to?

 

Interesting - sounds like the same scenario we have. 1800s cottage with brick floor topped with concrete. 

 

I think cost must start to look less daunting when you consider less labour to install blinding, type 1, concrete, PIR with a traditional slab?

 

Out of interest did you install DPM and traditional screed with UFH? People seem keen to top with limecrete and leave vapour open.....

[BenP]

1 hour ago, Russdl said:

What floor U value should I be aiming for for a detached garage/workshop?

 

I can't find any guidance unless it's for a garage conversion, can someone point me to any guidance?

 

There's no required amount as it's considered an unheated space by Building Regs. 

 

If you're considering heating it anyway you're going to want 0.18-0.21 I'd say. 

[saveasteading]

 Sitting it on some aggregate does nof seem adequate, other than for a temporary or lightweight building. Garden shed yes, garage no.

And you don't need insulation under the slab for these purposes....why not use local stone?

[Russdl]

@BenP thanks for that.

 

I was initially thinking of 300mm which it transpires would give me a U value of 0.19W/m²K so that looks alright (250mm would give a U value of 0.21W/m²K). Heating hasn't been decided yet.

[Russdl]

@saveasteading they put houses, commercial buildings etc on this stuff. It seems a garage would not present an issue.

 

5 minutes ago, saveasteading said:

And you don't need insulation under the slab for these purposes....why not use local stone?

 

I may not need the insulation but I do want it so that, as a workshop, it's a reasonable environment year round.