Internal insulation - Wood fibre vs dry lining

[a twig]

@thebadger7 what county are you based in?

@CarolineTheChemist - we have cement repointing which we want to rectify. How expensive is that process? Did they replace it with traditional fat lime mortar (hydraulic)?

Hydraulic and Fat are different

 

[NecessaryWing]

Hydraulic and Fat are different

Whoops. Yes they are - meant non hydraulic (I think). The lime putty I should have said.

 

[Lacan07]

Whoops. Yes they are - meant non hydraulic (I think). The lime putty I should have said.

The terms are very confusing. 'NHL' stands for Natural Hydraulic lime which can set under water and doesn't involve lime putty, but theres also 'Hydrated' lime which comes in a powder and can be turned into putty with the addition of water. Some people refer to Hydrated lime as 'Non-Hydraulic' lime which easily gets confused with 'NHL'

 

[DampedOut]

Hi, I'm no expert on stone walls, are they susceptible to freeze/thaw in the same way that a brick is? That's the main issue with brick, especially the old soft variety, if you remove some of the heat they receive in the winter with IWI and the bricks are damp then they freeze internally and the face gets blown off. I think its called 'spalding'? Then they are no longer protected from the elements.

I guess stone walls are a hell of a lot thicker too?

Ah, thanks! I was just wondering about it because I'd done loads of calculation and figured out that for the house I'm thinking about (80cm sandstone walls) it would take 12cm of wood fibre insulation to achieve the building regulation standard (get an equal or better than .30 U value).

The idea of doing all that and then the required amount of insulation causing freeze-thaw damage to the stone facade was just awful. What is the actual point if it will damage the historical heritage of the building?

Depends on the density of the stone. Roughly speaking density relates to porosity and as a consequence even the hardest stone can absorb some water through its surface and spalling damage can ensue. Just not as quickly as a manufactured brick I'd guess.

Thanks for this! I'll bear it in mind. I think sandstone is pretty porous, so actually going for strong insulation could be a bad idea. Maybe medium-strong or just medium is the better choice.

 

[CarolineTheChemist]

@thebadger7 what county are you based in?

@CarolineTheChemist - we have cement repointing which we want to rectify. How expensive is that process? Did they replace it with traditional fat lime mortar (hydraulic)?

Sorry for the very late reply!
It wasn’t that expensive, I think around £900 for 3 days of work for two guys.

 

[erikwoolf]

Did you have to remove the wallpaper from the walls that you installed the woodfibre? I did that for most walls however there are a couple of small sections that I have removed the newest layer of wallpaper and remains a much thinner older layer. It is much more tricky to remove that original layer so I was thinking to put the woodfibre on top of that.. Has anyone got any experience and do you see any issues with that approach?

 

[Toby Newell]

Hi, I'm no expert on stone walls, are they susceptible to freeze/thaw in the same way that a brick is? That's the main issue with brick, especially the old soft variety, if you remove some of the heat they receive in the winter with IWI and the bricks are damp then they freeze internally and the face gets blown off. I think its called 'spalding'? Then they are no longer protected from the elements.

I guess stone walls are a hell of a lot thicker too?

Limestone spalls very badly due to its porous nature, worse than many bricks.