Degredation of lime/sand mortar wall after cavity insulation

Olitaylor · 13 Sep 2007

I am considering cavity wall insulation, but after reading some of the posts here, it seems like it's more trouble then it's worth....?

My house was built in 1897 and the exterior walls seem to use a yellowy sandy mortar that seems to be a bit crumbly in places, along with a couple of the bricks.

If I use cavity wall insulation, I am worried that the external wall will be more prone to storing moisture as it can't evaporate into the cavity, and as a result the brickwork and mortar will degrade much faster....

DOes anyone have any experience or advice on this?

JohnD · 13 Sep 2007

Your house was built in 1897...

How do you know it's got cavity walls?

Olitaylor · 13 Sep 2007

Yes, I was surprised too, but apparently it has....we are having some wall ties replaced in the front wall, so I guess it must have!

I guess maybe I have the date wrong, but I've seen the original deeds and they say 1897. It's definitely of Victorian look!

You have me worried now, How would I know from looking at the house?

JohnD · 13 Sep 2007

measure the thickness of the walls, at a door or window.

9" is single

11" is cavity

you can also tell by looking at the patten of brics.

can you post some pics?

joe-90 · 13 Sep 2007

Look for 'headers'. That means bricks that are laid across the wall and look like half size bricks.

Fluffster · 13 Sep 2007

You may find it has a finger cavity which I would not get filled as it will cause the problems you mention.
Pete

Olitaylor · 13 Sep 2007

Hmm,

OK, I will have a look at the wall, I will take some pictures, but can't do that until tomorrow.

thanks for all your posts so far...it seems like cavity wall insulation is a bit hit and miss unless it's actually designed into the building then?

Fluffster · 13 Sep 2007

I had my walls filled ,4inch cavity and the difference in heat loss / retention is excellent well worth it with no probs of damp bridging.
Pete

blondini · 19 Sep 2007

My house has rows of headers in the outside brickwork that fool everyone into thinking that it is just solid 9" but the overall thickness of the walls is nearly twice that.

Built around 1915 it has cavity walls with 9" outer leaf and 4.5" inner. The cavity measures about 2.5" I've never seen another house like it.

JohnD · 19 Sep 2007

I've seen it in large and expensive houses built around 1880 to 1910

I presume it was a very good quality method of building.

The-brickie · 22 Sep 2007

Currently working on a house built in 1897 which is cavity walling, nasty sharp fish tail type ties.

diynot

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

Degredation of lime/sand mortar wall after cavity insulation

Similar threads