Diasen Diathonite

[mh12]

Uninsulated wall*​	2.19​	2.19​
20​	1.07​	0.97​
30​	0.86​	0.77​
40​	0.72​	0.63​

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Wall Type​

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Thickness of Application (mm)​

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Diathonite Evolution
U-Value (W/m²K)​

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Diathonite Thermactive
U-Value (W/m²K)​

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220mm brick​

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I'm trying to figure out how much of an insulating improvement having say 30mm of this product make compared to standard lime plaster of 20 mm thickness?

To get meaningful improvements a significant thickness of insulating plaster needs to be applied which is not feasible but in some locations this plaster I think has a place say bathrooms and rooms where cornices need to be preserved i.e. in locations where IWI is not practical.

Hmmm, is IWI contra indicated in bathrooms given the inherent risk of condensation/moisture generation ?

 

[larry]

I'm interested in thoughts about this only as I had also researched this product when considering options...

Also aerogel plaster, is seriously love some real world experience....

Mh12, for our bathroom we did use wood fibre, mike eye indicated 100mm was fine and suitable for bathroom use. I guess with wood fibre the hygroscopic nature is helpful in a bathroom.

We do have MVHR though which is amazing at clearing condensation post shower (though I installed that after putting the wood fibre in the bathroom )

 

[mh12]

Thank you for the response, Larry.

I also would like to got down the woodfibre IWI route for the bathroom, insulation thickness possibly 50mm , at the moment thought undecided between mechanical fix for the stiff WF boards OR fluff WF installation between studs.

Could you share please the make up for your bathroom walls. (IWI mechanically fixed or between battens)

I'm guessing parge coat, 100mm IWI, lime finish in 2 passes with mesh between the 2 passes, breathable paint.

My better half would prefer to have all the the bathroom walls tiled. Now is that a contra-indication for wall breathability and does it defeat the purpose of using breathable IWI?

Out of interest did you opt for decentralised MHVR in the bathroom?

I was thinking of a powerful extractor fan but will consider decentralised MHVR is it is more advantageous.

 

[larry]

Thank you for the response, Larry.

I also would like to got down the woodfibre IWI route for the bathroom, insulation thickness possibly 50mm , at the moment thought undecided between mechanical fix for the stiff WF boards OR fluff WF installation between studs.

Could you share please the make up for your bathroom walls. (IWI mechanically fixed or between battens)

I'm guessing parge coat, 100mm IWI, lime finish in 2 passes with mesh between the 2 passes, breathable paint.

My better half would prefer to have all the the bathroom walls tiled. Now is that a contra-indication for wall breathability and does it defeat the purpose of using breathable IWI?

Out of interest did you opt for decentralised MHVR in the bathroom?

I was thinking of a powerful extractor fan but will consider decentralised MHVR is it is more advantageous.

Yes - the make up is exactly what you say. That part of the house was the first bit that I did and we used rigid wood fibre with the plaster that Mike Wye specified. I've experimented a lot since then!

Re: tiling. Yes, Porcelalain tiles will certainly be very vapour impereable; ceramic tiles I don't know, but I think the idea is that it breathes through the grout... are there any lime based bathroom friendly grouts out there I wonder? (never had to look). Alternatively I think a small section of wall not breathable should be OK as the moisture can move aroud the blockage. I have no idea about tiling on wood fibre though...

We've got a whole house MVHR and I love it. Apart from getting rid of moisture after showering very quickly without having to lose any of that precious heat, it's also superb for getting rid of the lamb smell after a sunday roast (apologies to any vegetarians...). I've used one decrantalised MVHR on another family house, a cheapish one and wasn't terribly impressed, IIRC they work best where you have two at opposing ends of the building. One of the issues was you could only get to the filter by removing the facia of the fan unit and pulling out the heat exchanger. It was also much more noisy than the whole house one we have (no more so than a bathroom fan). So I'd probably recommend actually having a good look at the unit itself before buying one.
[I completely understand the arguments about whole house MVHR for old houses being pointless as the house is nowhere near airgith, but we've been quite conscietnious at trying to stop draughts etc, and to be honest it stops me keeping a window open on a cold day to vent the shower, I'm winning from an energy perspective]