Poured floor insulation (Thermal lightweight aggregate))

[Annker]

Morning all,

 

I have been aware of TLA (thermal lightweight aggregate) as a construction product but more so used in large commercial projects but it now seems to be offered as a poured insulation subfloor to domestic project. https://www.energystoreltd.com/professional, this company seem to been a product wholesaler not a actual contractor. 

 

Just wondering if anyone has any experience of using this in a domestic project.

 

In my experience fitting PIR floor insulation is a nightmare of a job for a whole range of reasons.

Its a time consuming job, cutting the insulation around pipework to ensure a continuous fit of insulation all over the floor is near impossible and furthermore which contractors do you get to do it.

 

A poured insulation seems to have many benefits, waste free, storage free, better performance. 

Is it not yet commonly used in domestic project due to cost or just hasn't been rolled out yet?      

 

Keen to hear your opinion! 

 

[ETC]

I don’t think it will act as a sub-floor. It’s more of a poured insulation/screed and does remove the need to cut the PIR insulation around pipes. However I do believe that you will need quite a bit more of the insulated screed than you would PIR so check with your SAP assessor for the thickness required.

 

You will also need to think about where your DPM should be located and more than likely you will need a VCL and perimeter insulation before you place the final screed.

 

I have experienced contractors laying the heating pipework above the sub-floor slab, covering it in the DPM and then pouring just enough insulated screed to cover the pipework leaving a flat surface to lay PIR insulation on. Then it’s just laying the VCL and placing the perimeter insulation before placing the final screed.

 

In any case speak to your BCO and SAP assessor before you go down this route so that everyone is singing off the same hymn sheet.

[Annker]

Yes correct, AFAIK it isn't a substitute for the structural concrete subfloor; perhaps it can be designed so but in any case I am just thinking of it as an alternative to PIR.

 

I think in any arrangement the DPM will always be located above pipework to ensure continuity but under the poured insulation.

 

If I read you post correct you are essentially using this method but reducing the thickness of poured insulation in favour of PIR to meet U-valve?

Its the junction of insulation (of whatever type) around the pipework that is problematic so I think you are hitting the mark with your hybrid design and it gets you over the pipework!

 

Do you buy in ready mixed pourable insulation or does the contractor just site mix a lean mix with vermiculite?

 

On my last project I first fitted 70mm PIR squarely ( not scribed to the pipework) to the floor fixed pipework, if that make sense, and then infilled over the pipework runs with a lean mix/vermiculite flush to the top of that first 70mm PIR layer.

That got over the pipework and allowed a 2nd layer of 70mm PIR to run continually uninterrupted.    

  

 

 

 

[A_L]

1 hour ago, Annker said:

A poured insulation seems to have many benefits, waste free, storage free, better performance. 

 

The most insulating grade TLA110 has a thermal conductivity of 0.043W/m.K compared to PIR of 0.023W/m.K so you will need 0.043/0.23 or 1.87 times the thickness to compensate.

[Annker]

6 minutes ago, A_L said:

 

The most insulating grade TLA110 has a thermal conductivity of 0.043W/m.K compared to PIR of 0.023W/m.K so you will need 0.043/0.23 or 1.87 times the thickness to compensate.

Apologies, I didn't mean better performance in W/m.k but in that poured insulation is a continuous layer.

I'm a carpenter by trade so relatively skilled at cutting, fitting and installations but even for me cutting in floor insulation around pipe runs is nearly impossible, its a very poor arrangement and surely a lot that PIR U-value performance is lost here.

     

[Conor]

We're using it on our intermediate floors before we lay our ufh. It works out slightly more than PIR but that's before you factor in the faff of laying the boards flat on uneven slabs. If using it for you gound floor insualtion, you need at least double depth compared to PIR.

 

No prep or membranes required on intermediate floors - just shuttering voids.

[Gordo]

5 hours ago, Annker said:

Do you buy in ready mixed pourable insulation or does the contractor just site mix a lean mix with vermiculite?

 

On my last project I first fitted 70mm PIR squarely ( not scribed to the pipework) to the floor fixed pipework, if that make sense, and then infilled over the pipework runs with a lean mix/vermiculite flush to the top of that first 70mm PIR layer.

That got over the pipework and allowed a 2nd layer of 70mm PIR to run continually uninterrupted.    

  

 

 

 

It is a supply and fit specialist job. 
 

Heating pipes MUST be fitted on top of insulation within the heated/insulated envelope. Anyone who fits heating pipes (without serious thickness lagging) under insulation are foolish.

Edited November 10, 2021 by Gordo

[ETC]

4 hours ago, Conor said:

We're using it on our intermediate floors before we lay our ufh. It works out slightly more than PIR but that's before you factor in the faff of laying the boards flat on uneven slabs. If using it for you gound floor insualtion, you need at least double depth compared to PIR.

 

No prep or membranes required on intermediate floors - just shuttering voids.

 

You’ll still need the DPM under the insulated screed at ground floor level. Not sure why you’d use the insulated screed at first floor level though?

 

5 hours ago, Annker said:

I think in any arrangement the DPM will always be located above pipework to ensure continuity but under the poured insulation.

Correct. And overlapped and continuous with the wall DPCs.

 

If I read you post correct you are essentially using this method but reducing the thickness of poured insulation in favour of PIR to meet U-valve?

Correct. And to give a level base for the PIR.

 

Do you buy in ready mixed pourable insulation or does the contractor just site mix a lean mix with vermiculite?

Contractor mixed and poured from a big lorry on site. 

 

[Annker]

1 hour ago, Gordo said:

It is a supply and fit specialist job. 
 

Heating pipes MUST be fitted on top of insulation within the heated/insulated envelope. Anyone who fits heating pipes (without serious thickness lagging) under insulation are foolish.

Tbh I think its common and accepted practice to have heating flow & returns fixed to the sub floor (lagged of course), not saying it is the most energy efficient.

If fact I'm not sure how it could be avoided where wet UFH pipework is also being installed in the build-up?

 

Of course the hot primary's could be ran under/in first floor level and dropped down to ground where needed.

That is actually an arrangement I'd like to explore as it also would allow potential leaks to be much easily identified and accessed for repair.   

  

[Gordo]

1 hour ago, Annker said:

Tbh I think its common and accepted practice to have heating flow & returns fixed to the sub floor (lagged of course), not saying it is the most energy efficient.

If fact I'm not sure how it could be avoided where wet UFH pipework is also being installed in the build-up?

 

Of course the hot primary's could be ran under/in first floor level and dropped down to ground where needed.

That is actually an arrangement I'd like to explore as it also would allow potential leaks to be much easily identified and accessed for repair.   

  

Do as you chose to do. I have see it in practice often and advise it is is extremely poor practice. Often the cheapest grey polythene 9mm thick lagging too. Obviously there are a lot of people out there who have not given this much thought. The plumbers don’t seem to care from the reaction I have got, the builders don’t seem too interested as it’s a plumbers thing and the clients don’t know any better. 
 

Just letting people know that this should not be accepted normal practice if you care about conservation of energy. Heating pipes should be within the screed or laid on at least 25mm thick PUR insulation (with remainder of insulation thickness between pipes). If it is just the primary pipes that’s not quite so bad, these could be properly lagged with 25mm quality lagging as a minimum.

Edited November 10, 2021 by Gordo

[Annker]

4 hours ago, Gordo said:

Do as you chose to do. I have see it in practice often and advise it is is extremely poor practice. Often the cheapest grey polythene 9mm thick lagging too. Obviously there are a lot of people out there who have not given this much thought. The plumbers don’t seem to care from the reaction I have got, the builders don’t seem too interested as it’s a plumbers thing and the clients don’t know any better. 
 

Just letting people know that this should not be accepted normal practice if you care about conservation of energy. Heating pipes should be within the screed or laid on at least 25mm thick PUR insulation (with remainder of insulation thickness between pipes). If it is just the primary pipes that’s not quite so bad, these could be properly lagged with 25mm quality lagging as a minimum.

Totally agreed with all the above. 

Unfortunately advancement of better practices in the building game is frequently hampered by an attitude of "it's always been done this way"  

 

Any experience in running pipework under or in the 1st floor level ceiling void?

This is typical arrangement in commercial project but I cant recall seeing this in domestic residential builds.    

[Gordo]

On 10/11/2021 at 23:21, Annker said:

Totally agreed with all the above. 

Unfortunately advancement of better practices in the building game is frequently hampered by an attitude of "it's always been done this way"  

 

Any experience in running pipework under or in the 1st floor level ceiling void?

This is typical arrangement in commercial project but I cant recall seeing this in domestic residential builds.    

I’m not to sure what you are describing TBH. As this sounds common enough in domestic to route pipes in or under first floor voids. I’m not mush of an expert in plumbing but I do see a lot going on.

[Conor]

On 10/11/2021 at 23:21, Annker said:

 

 

Any experience in running pipework under or in the 1st floor level ceiling void?

This is typical arrangement in commercial project but I cant recall seeing this in domestic residential builds.    

 We have everything in the ceiling void. From the basement buffer tank, the 22mm pipes go though a service cavity and along the ceiling voids to the manifold. Only thing in the floor is ufh pipes and the odd bit of waste pipe.

[Gordo]

1 hour ago, Conor said:

 We have everything in the ceiling void. From the basement buffer tank, the 22mm pipes go though a service cavity and along the ceiling voids to the manifold. Only thing in the floor is ufh pipes and the odd bit of waste pipe.

Should be all good if in heated envelope then. So long as primary flow and return between boiler and buffer tank is well insulated. Assuming the basement is insulated. If not make sure pipes down there are well lagged I guess.

[Annker]

3 hours ago, Gordo said:

I’m not to sure what you are describing TBH. As this sounds common enough in domestic to route pipes in or under first floor voids. I’m not mush of an expert in plumbing but I do see a lot going on.

I should have been clearer, I'm referring to pipework serving heating/sanitary installation on the ground floor (say heating F&R to radiators, domestic hot and colds to WHBs) 

These are typical ran in the ground floor build up and turned up to their relevant radiator/sanitary ware.

 

Personally I have very rarely seen that ground floor serving pipework ran at high level (be that within 1st floor joisting void or under 1st joisting/above a false ceiling )and then turned down the walls, although I can imagine there are benefits to it; such as easy of future access if needed 

[Gordo]

On 12/11/2021 at 18:16, Annker said:

I should have been clearer, I'm referring to pipework serving heating/sanitary installation on the ground floor (say heating F&R to radiators, domestic hot and colds to WHBs) 

These are typical ran in the ground floor build up and turned up to their relevant radiator/sanitary ware.

 

Personally I have very rarely seen that ground floor serving pipework ran at high level (be that within 1st floor joisting void or under 1st joisting/above a false ceiling )and then turned down the walls, although I can imagine there are benefits to it; such as easy of future access if needed 

I pretty sure I have seen this in one off timber frames but not sure and didn’t think to much about it at time. the majority of timber frames they are run within the walls which I really don’t like. I think you idea would have really good merit worth considering. I guess plumbers don’t like forcing/pumping hot water down wards as plumbing convention has it that heat rises, but don’t think that matters with a modern pumped system. I’m sure there is a plumber out there how could advise us on this

Edited November 13, 2021 by Gordo