Masonry Cream - is it all it's cracked up to be?

[Linda Secker]

Hi all - do any of you know if the new generation of masonry treatments are all they are cracked up to be?? We don't have a damp problem, but we do have cold, solid stone walls.

We've had a quote of £1800 to apply this stuff (after pressure washing and making good some fairly ropy pointing) on our Victorian terrace, but we are now stressing about it.....

 

[Burnerman]

It sounds like you are referring to an injected damp proofing solution here? For what it is, it works fine in an ideal situation.
If you consider your stone to be porous, Johnstones Water Seal works well enough too.
Any poor pointing must be remedied with the appropriate lime mortar.
Can you expand on what your work proposal is, please?
John

 

[^woody^]

If you are referring to the silane coatings to waterproof masonry walls, then yes they do work.

They do the same as Thompsons, but last many years longer as they resist breakdown by UV light.

They are for waterproofing only, possibly enhanced frost resistance (but check the product for this), but certainly don't do a thing to make cold walls any warmer.

 

[Linda Secker]

Hi Burnerman

The proposal is to power wash, repoint where necessary (some will come out with the washing, some is already off, most is perfectly sound) and then to coat the walls with the masonry cream.

The stuff is meant to be completely waterproof (sheds water and dirt by beading) soaks into porous stone and mortar up to 17mm depth and dries to a breathable, clear coating lasting minimum 10 years.

By keeping the walls completely dry, it's meant to improve the thermal properties - which would be very usuful, but is where I'm not sure how true it can be!!!

It's not injected, it just soaks in and coats......

We have solid, stone walls and the house is COLD, but this does sound a little too good to be true??

 

[Linda Secker]

Hi Woody - it's the next generation stuff - nano beads?? This one is called proPERLA but here is another called stormdry for instance..... we did use 'waterseal' about 10 years ago, but I would guess that needs redoing now - also this new stuff is supposed to be breathable which would be good... however, I am getting twitchy about the cost....

 

[footprints]

I looked at a house that had that coating applied, it put me off buying, as it might well cover any number of problems.

 

[^woody^]

By keeping the walls completely dry, it's meant to improve the thermal properties

That's not true at all. Any firm using this as a sales pitch is either plainly lying, clueless, or both, and I would seriously question their integrity.

Ask them for some independent test results for those claims, and certification from a testing authority such as the BBA.

 

[^woody^]

I looked at a house that had that coating applied

The coating is invisible and has no sheen! You can only see it when applied as it's white.

 

[^woody^]

It's basically this stuff which is £83 a tub

www.twistfix.co.uk/dry-seal-water-repellent-cream

 

[^woody^]

That properla claim is outrageous. 30% energy saving . WTF? That's better than any wall insulation.

 

[bernardgreen]

By keeping the walls completely dry, it's meant to improve the thermal properties

That's not true at all. Any firm using this as a sales pitch is either plainly lying, clueless, or both, and I would seriously question their integrity.

There is some truth in the claim. A damp wall will be chilled by evaporation ( similar to the wind chill effect ) and will be below ambient temperature. By preventing that chill effect ( keeping the wall dry ) will reduce the heat loss through the wall. On a thin masonary wall without a cavity the reduction in heat loss is significant. The claim of Up to 30% is not dishonest if there is a 0.1% reduction. It would be wrong to say that if there was any chance of the reduction being more than 30%

 

[Linda Secker]

yes that's what I was thinking - but is it better than the significantly cheaper Thompsons water seal?? and is that breathable? Basically, IF the walls get damp, we will be losing extra heat through them due to evaporation, but we could stop that with 'water seal' However, if water seal is not breathable, we are getting damp inside due to condensation.....

dunno what to do!!

 

[^woody^]

There is some truth in the claim.

A damp wall will be chilled by evaporation

There is no truth in the claim. Heat transmission from an internal room is not going to be any greater due to evaporation from the outer surface of a wall. It does not work like that.

Evaporation does not draw heat out of a house. That's pseudo-science mumbo jumbo.

 

[bernardgreen]

Evaporation does not draw heat out of a house. That's pseudo-science mumbo jumbo.

Evergreen climbers provide winter insulation, by not only by maintaining a pillow of air between the plant and the wall, but by reducing wind chill on the wall surface. Reducing wind chill by 75% can reduce heating demand by 25% (Peck et al 1999). Reduction of wind chill is also reduced to some extent by the interwoven stems of deciduous climbers during winter. The effectiveness of winter insulation is related to the thickness of growth, which is generally related to the age of the plant. In some cases however growth patterns change as the plant ages, e.g. there may be a reduction in the dense twiggy growth that forms the most effective insulation.

Also confirmed by the Q-value calculations for the breathing walls in the Walter Segal house we built in 1980.

 

[footprints]

Perhaps not the coating I saw that had been applied, a bit like a Tyrolean finish.
However when these claims for products (like insulation sprayed on the underside of the roof) appear the term "Snake Oil" comes to mind.