Cracked cement rendering, damp penetration, 1950s house

[PK]

Our 1950s property was once Mock Tudor (brick on ground floor, rendered and cosmetic timbering on upper floor). At some stage in the past, for an unknown reason, the cosmetic timbering has been removed, and infilled with render, and the ground floor has been rendered.

As the house is on a slight hill, on a clay over chalk soil, and has a mature birch tree within 4 m of the house, there is some movement and the rendering is covered in small cracks, including where the timber was removed. We have patches of damp at intervals on the worst wall, which I am sure are caused by water penetrating the cracked rendering.

We also have mouldy patches appearing behind bedroom furniture, which, after reading a lot of this forum, I suspect may be caused by the rendering trapping condensation, even though the windows are open at night

I should add that the walls are not cavity walls.

Also the internal plasterwork is rather strange, being of drill-breaking hardness.

My questions are:

Would lime-based rendering be suitable for a property this age?

Would it cope with the movement of the house?

Would it solve the water penetration and mould problems?

Can anyone provide an approximate cost per meter squared, including removing old cement rendering?

 

[middi]

Hello, PK.

Reading detween the lines, it appears that water is filtrating behind the exterior rendering and nowhere to go once there.

It is not clear without the benefit of a proper investigation if the water is getting access from the removed mock-tudor planks repaired render filling or due to the tree heaving the ground cracking render( and brickwork !!), or both.

There is little point in deciding how and what to repair unless you invest on the services of a surveyor, if you are unable to determine this yourself.

In the event that you decide to re-render the exterior I suggest you stick to the original ( 1950,s) render mix, before you do any of this you have to satisfy yourself that the tree is not causing the cracks.

Lime render will not stop the water ingress, it will assist on a fast evaporation and drying cycle, it is also malleable enough to assist towards any building movement over a period of time but not enough to cope with the roots of a vigorous tree next to a building foundation.

It is of little use using lime renders where used in conjunction with existing cement renders or cement based mortar used for bricklaying.

As to how much per sq. meter to remove or replace render, that very much depends on who do you use to get the job done, how much of the work is undertaken by yourself and what materials eventually you will be using.

Once it is decided exactly the work to be done, just get two or three local quotes for the job, it is usually the best way.( and try and negotiate ! )

 

[NT]

quote="PK"

> Also the internal plasterwork is rather strange, being of drill-breaking hardness.

cement presumably, with a plaster skim.


>Would lime-based rendering be suitable for a property this age?

if its brick built, yes. But if its poured concrete it wouldnt be the best option.

>Would it cope with the movement of the house?

upto a point, more so than cement at least

>Would it solve the water penetration and mould problems?

it would either solve or improve them


>Can anyone provide an approximate cost per meter squared, including removing old cement rendering?[/quote]

not much if you DIY, lime is £6 a bag and sand £2. An SDS drill is under £100.


NT

 

[Lime]

Perhaps I'm stating the obvious but is the dampproof course covered over by the ground floor rendering?

Also if the plaster turns out to be cement as NT suggests then that could cause dampness (through condensation) all by itself IMO.