Has anyone used Wallrock thermal liner?

[WhenSheWasBadSheWasHopeful]

Having a major disagreement with dh about wallrock. We have a stupidly cold Victorian house (it's old but has a cavity). Dh has banned cavity wall insulation saying the brick work is not up to scratch and the wall ties have debris on them.

We are decorating the end bedroom and I think it would make sense to put some Wallrock up but dh disagrees. He says at 3mm it is too thin actually insulate well.

I agree with him but I think the benefit would be

1. the wallrock stuff is warmer to the touch than a cold wall so the house would heat up quicker (we turn the heating on in the morning and again in the late afternoon so house is not at a constant temperature).
   
2. the bed in that room will be right next to the wall so having a warm to the touch wall rather than a cold to the touch wall will feel warmer.
   
   Also the reviews for it on b&q website look very positive, most say it has actually made their rooms warmer.
   
   
   Has anyone actually used this stuff? Did it make any difference?

[BrownSauceSandwich]

Is your husband qualified to judge on the cavity walls? Is he not just being a bit contrary? Honestly, I'd want an expert opinion before going up hope of a cheap and very effective method of insulation. Debris on the wall ties??? I really can't imagine what that's supposed to mean.

Anyway, I can't tell you anything about wallrock, so all I can suggest is that you try to find out whether your husband is just a bit bah-humbug about the whole insulation thing, and push for cavity wall insulation (tried and trusted) if at all possible.

[WhenSheWasBadSheWasHopeful]

Thanks for the reply. He is a bit bah-humbug re cavity wall insulation. Trouble is builders tend to agree with him "it's got a cavity for a reason" etc etc.

Builders seem to care more about the building than the people living freezing inside them. Thing is there are scare stories about cavity wall insulation but then this is to be expected. Most of the time it is fine but sometimes there are issues.

I really don't think I'm going to sway him on the cavity wall thing, especially not when trades people give him horror stories on what can go wrong.

He is putting loads if insulation in the loft. We have two separate lofts and can only insulate the back one the front one has been converted so there's not much else we can do there.

[wonkylegs]

Your husbands concerns about cavity wall insulation have a valid basis. It can in some cases cause serious problems with penetrating damp, condensation and corrosion of wall ties.
On new houses cavity walls are designed so the damp doesn't penetrate further than the outer leaf of brickwork, there is usually a gap & a membrane lining to ensure any damp from wind driven rain that gets into the cavity drains down the inside cavity and is released back outside.
Retro fitted cavity wall insulation doesn't have this and can in some cases act as a bridge for penetrating water to the inner leaf of the wall causing damp, the wet cavity can also lead to premature corrosion of wall ties. This is more likely on a Victorian cavity wall than a larger modern cavity wall. Lots of the companies that put the CWI in also don't have the best reputations.
Examples of problems here
I don't know about the wallboard you are asking about but logically in insulation terms it's likely to little difference and it's more likely a psychological effect.
To get any real difference you need to batten out and insulate the inside of the wall and plasterboard over the top. It'll make the room slightly smaller and is a faff to do (got to remove & reinstall sockets/switches/skirting etc) but it will work.
Interesting article on different options for a Victorian house here they discuss thermal lining and how it's a bit pointless.

[WhenSheWasBadSheWasHopeful]

wonky are you my dh?

I'll have a look at those links, thanks.

[wonkylegs]

Ha, nope.
I'm an architect and I can't help myself but I like to explain my decisions thoroughly when talking to clients so they can understand why I'm saying stuff.... And I guess that overspills to my answers on MN too sorry
Hope something in there is useful.

[Daisybell1]

We're going for internal insulation (solid walls so can't have cwi) whenever we do up a room. We had the 100mm stuff put in our bedroom which has made a huge difference.

We're toying between the newer 27?mm insulation or sheep's fleece downstairs depending on how breathable we need it to be.

[WhenSheWasBadSheWasHopeful]

daisy 100mm sounds like a lot of space to loose. Was it noticeable?

We could do it in the back bedroom but we have loads of original features I don't want to lose. Could do the external cladding but it sounds soooo expensive.

wonky you really shouldn't have told me you are an architect, I might start stalking you. What if we got our outside walls rendered so we know water won't be getting in. Could we do the cavity wall insulation then?

[PigletJohn]

3mm of expensive foamy on the wall will not make any material difference.

There are far more scare stories about CWI than actual problems. If you have a defective wall with holes in it or loose render; or a gutter spilling water down the wall, then you need to fix it. If you have a cavity filled with builders rubble then it should not be there (it is quite tiresome to remove)

In the rare cases where the CWI has been wrongly installed in a wall where it shouldn't have been, I have known the installers be forced to vacuum it out again. With modern loose-fill mineral wool this is not especially difficult. The wool I have seen is treated so that it is hydroscopic and will not get wet or damp. If you hold a handful in a bucket of water, when you lift it out, the water runs off and it is dry.

There are some chronically wet walls where it should not be installed until the wet has been addressed. For example I am in a coastal location, and the wall facing the weather is slate-hung. In storms rain comes off it in a waterfall. However most of my neighbours have modern cavity brick walls facing the weather, with CWI, no tiles, and no damp.

You can usually buy it from your gas or electricity company at a good price; they are highly unlikely to go bust or run off if there is a problem. It's not like complaining to a double-glazing or a kitchen fitting company.

Mine knocked more than 25% off my winter gas usage.

[Daisybell1]

We did it all the way down but it was actually my moving in present so I don't know what the room was like before!

We also have original features - there is moulding around the window bay and our joiner lifted it off the wall and refitted it over the insulation. As part of the works we found a Georgian fireplace with hearth which we've opened up.

I take your point Pigletjohn about 30mm not making much difference - I'd rather go for another 100mm depth downstairs and know that it would work!

[PigletJohn]

3mm is the "wallrock" which is a sort of fancy wallpaper with slight insulating properties.

30mm would be worth having.

[Choccybaby]

Would external wall insulation be an option?
It tends to be more effective than internal with no potential damp or cold bridging problems than cwi can have.

[WhenSheWasBadSheWasHopeful]

Thanks piglet I agree with you about there being more scare stories re cavity wall than there are actual problems. You never hear about the successful ones only where it's gone wrong.

choccy the external insulation could work but it sounds so expensive. Also we are in a semi so I'm not sure how it would look with our neighbours staying the same.

[WhenSheWasBadSheWasHopeful]

Ok I've been thinking. We need to get our gable end rendered anyway, we are similar to piglet in that we live on a coastal area.

The gable end is where all the rain hits the house and we have a problem with blown bricks.

So could we do a thermal render on that wall? Does anyone have any clue how much more expensive a thermal render is compared with normal I really hope wonky is still on the thread

[PigletJohn]

I have seen external insulation done in Switzerland, but the big manufacturers (Kingspan, Knauf, Celotex) do sell the materials over here. Not many builders will have done it.

It was done by bolting slabs of rigid foam to the outside wall, then fixing a cement-fibre board over the top, and a thin decorative render over the board. I suppose it took two or three days per house.

As it adds thickness to the wall you would have to look at your eaves or roof projection to see how to stop rain getting behind it. The swiss houses had big eaves but a british gable is often flush.

[wonkylegs]

Yep still here, I'll try to answer whilst I wait for a call back from a window company & the school. Ha juggling work & school holidays is rubbish!
Insulated render has been used in this country and if done well can suit some houses well. Quite a few of the councils/HAs have used it to upgrade their housing stock.
You do need as PigletJohn says to consider window reveals/eaves etc otherwise you end up with fat walls that don't work where there is a detail.
You probably need to look at slightly larger render companies to do the work as they are more likely to have previous experience.
I've personally not used it as a retrofit solution(only new build) so I can't give an idea of costs (and I would be wary of a cost per m2 as it will vary hugely depending on the complexity of the job), I have however seen it used successfully and attractively by others so it may well be a possible and practical solution.
I think your best bet would be to get some guys out for quotes (make sure they have experience you can go & see before getting them out, so not to waste time on unsuitable people), you can always reevaluate after they've been round.

[WhenSheWasBadSheWasHopeful]

Ooh thanks for the advice. The eaves are not flush they probably jut out 9 inches or so (hard to tell they are a bit high up).

With us doing only one wall would we have an issue with the new render sticking out over the old wall where we will not be rendering?

we need the gable end doing, it's a semi so the front of the house would look normal then it's a rendered finish on the gable end towards the back of the house and the back would just be left as brick

[timbugg]

i used this in a house we just bought which had terrible wall condition and realy needed the walls skimming. my friend told me to use kv600 wallrock thermal liner instead and in has refinished the walls perfectly. a simple DIY Job and i am sure wil last for years. In addition we have warm rooms. You can get this here gowallpaper in the uk and they deliver next day. the page on there site is www.gowallpaper.co.uk/wallrock-range/wallrock-thermal-liner.html. hope this helps.

[PigletInABlanketJohn]

4mm is also rubbish.

[FRS2019]

Re wallrock products. If external, full internal or caverty wall insulation are impractical wallrock Thermal products are easy to apply and have a u value of 7 to 12 depending on the product. Wallrock graphite+ is cheaper and contains graphite particles that reflect heat equivalent to about 20cm of concrete. Although thin the heat reflecting properties actually does make a room feel noticeably warmer and reduces the feeling of cold damp in old houses for a reasonable cost and is easy to apply diy. Hope this helps.