external cement render

[pete32]

Hi,

I have a timber framed 17th century cottage and could do with a bit of advice if possible, the cement render on the front of the cottage has cracked in one area and is going to fall off in the not to distant future. My question is could I remove lets say a third of the front of the house from top to bottom and then remove the render insulate with sheepwool and re-render in lime and then do the other two thirds later on.

Some facts to give a clearer picture,

Internal walls are lime plaster and painted with limewash.
Timber frame has been repaired from the inside last year with new sole plate and vertical timbers where damaged.
Reason for not doing all of render is cash flow as I am attempting it myself.

Kind regards
Pete

 

[Moo]

could I remove lets say a third of the front of the house from top to bottom and then remove the render

Surely, once you have done the first, there won't be any render left to remove.
Or have I missed something?

 

[Penners]

Pete - I presume you mean remove the cement render from one third of the front wall, then do the rest at a later stage?

In theory I can't see why not. If you're removing the cement render, presumably the lath (EML?) will come off with it, so you'll have to be sure that the section you remove stops at a convenient stud each end, for fixing your new laths. And you'll have to get the best seal you can where the new lime render joins the old cement, in order to be weatherproof. But other than that, it all sounds feasible.

The lime experts say that lime has a "self-healing" property, so when you come to do the rest of the wall at a later date, make sure that you get rid of every scrap of cement, ensuring that you get a good lime-to-lime joint with the first section you did. This should enable the old and the new lime to knit together well.

I should add that I'm no lime expert - the above is views that I have formed from reading expert lime advice on this forum.

 

[Ian Bond]

Lime certainly is more tolerant of movement than gypsum and cement, from what I've observed. The lime has cracked but stayed firmly attached, whereas the more rigid materials have detached and fallen off in lumps.

It may in theory be self healing, but with enough movement lime renders will crack and won't miraculously mend themselves. A few coats of limewash will cover the tiny cracks, and you can easily fill in larger defects.

Patching with lime is difficult - you can't easily feather the repair in like you would with gypsum plaster, and joints will be visible to some extent, at least initially.

Again, several thin coats of limewash may help to disguise the join between old and new work.

 

[Ian Bond]

Are the other elevations OK?

You could always try patch-repairing the render first, so you can see for yourself if the finished result would be acceptable on the front of the building.

 

[pete32]

many thanks for all your comments,

The rear elevation is lime so this is ok, the side is in cement but is solid and has no signs of cracking. | was thinking of leaving the side for a few years, I know this is not the best scenario due to not allowing moisture to escape, but the internal walls our lime plastered so at least this will allow the timber work to breath. The other reason for only doing a small section of the front is I am worried that the more I uncover the more problems I will find so I was going to rectify a section at a time.

regards pete

 

[Penners]

I am worried that the more I uncover the more problems I will find

That's a sensible approach, because you're probably right.

Working on period properties tends to be like a game of catch-up - you set about replacing some crumbling plaster and find that this job exposes some rotten timber. You start replacing the rotten area and find that there's some dodgy wiring. You run a new length of cable and find loose brickwork.... and so on and so forth until you're too old to pursue the trail any farther.

Have a happy life! :wink: