Lime, Silicon Injection, or stain blocking paint?

[JHD]

In the house I'm hoping to buy there is an internal wall which has had the stud work exposed at the top above a low masonry wall which has a cement render. The masonry part of the wall is about 40cm high and the whole wall is about 2.5 meters wide.

The surveyor has noted high damp readings in the wall and evidence of past dry rot in the sole plate above (there's also discolouration in the paintwork). He has recommended replacing the cement render with lime to allow evaporation and drying out of the wall.

I can see that this is sensible advice so I got a quote from a contractor I've used before. It will cost approximately £1800 + VAT, which he admits is high but apparently it's because the work needs to be done over a number of days. The alternative he's suggested is silicon injection for £300 + VAT, or even using a stain blocking paint myself.

Thoughts? What would others do?

 

[TheForge]

Is the contractor a lime 'specialist' or standard builder?

As I read it you are being quoted nearly £2200 (after VAT has been added) to strip and lime plaster a wall with an area of about 1 square metre?! Am I missing something??

Silicone injection doesn't sound like the sort of thing a sympathetic conservation minded person would be suggesting either.

 

[Matt Green]

dry rot in the sole plate above

Dry rot in an oak sole plate? I think not. Brown rot, yes, but probably cellar rot or another wet rot- rubbish descriptors that those terms are.

The surveyor sounds a bit suspect.

 

[88v8]

With advice from those on here, you'll soon be able to knock the render off and redo it yourself in lime at a cost of peanuts.
DIY, the essence of owning a Period house.

Ivor

 

[tobydog]

JHD - three years ago I didn't even know what lime render/mortar was. I've since removed the cement render off my plinth walls, left them 6 months to dry out (good quality procrastination time), rendered in lime and limewashed. All learnt from the very helpful people on PPUK, books and the occasional one day course. It's so cheap as Ivor has mentioned. Just be careful with removing the cement because although it will probably and unfortunately remove some of the brickwork, it's good to keep it to a minimum. Just take your time and be happy that you've saved thousands and also saved your house walls from a lingering sticky death by silicone

 

[JHD]

Is the contractor a lime 'specialist' or standard builder?

As I read it you are being quoted nearly £2200 (after VAT has been added) to strip and lime plaster a wall with an area of about 1 square metre?! Am I missing something??

Silicone injection doesn't sound like the sort of thing a sympathetic conservation minded person would be suggesting either.

Yep - You got it right, it's only about 1 square metre, and why I'm kind of reluctant to spend that kind of money, even when I know it's the right method. I got the quote from a "damp, woodworm, and dry rot" specialist, but you perhaps I should find myself a lime specialist.

 

[JHD]

JHD - three years ago I didn't even know what lime render/mortar was. I've since removed the cement render off my plinth walls, left them 6 months to dry out (good quality procrastination time), rendered in lime and limewashed. All learnt from the very helpful people on PPUK, books and the occasional one day course. It's so cheap as Ivor has mentioned. Just be careful with removing the cement because although it will probably and unfortunately remove some of the brickwork, it's good to keep it to a minimum. Just take your time and be happy that you've saved thousands and also saved your house walls from a lingering sticky death by silicone

I'd started to wonder about doing in myself. I wouldn't describe myself as being practical, but I do tend to be methodical and a perfectionist so that might help. Has anyone been on a course that is is Cambridge / East Anglia way that they would recommend?

 

[tobydog]

Check this place out. It's just outside Needham Market. I've been on a few courses and if you read the blurb you will see it's all for a good cause. All students actually work on the barn which I first saw as a shell. If you contact Sarah she will tell you when the next lime course is. They also do timber framing and old house maintenance courses amongst many other things. The chap who runs the timber courses is Rick Lewis who owns Traditional Oak Carpentry. His Projects in the website below are pretty impressive.

http://www.orchardbarn.org.uk/

http://traditionaloakcarpentry.co.uk/

 

[skier-hughes]

For one square metre, you could do it about ten times before you reached the price of going on a course and have it perfected!!!!
I'd buy some ready mixed lime plaster, haired undercoat for bases 1 and 2, and a fine top coat for the top.
Plenty of reading on here and on web to learn how to do it, but nothing beats doing it to learn.

http://www.lime.org.uk/products/mortars-and-plasters/lime-plasters/lime-base-coat-plaster-for-scratch-and-float-coats/

http://www.lime.org.uk/products/mortars-and-plasters/lime-plasters/lime-top-coat-finish-plaster/

£4.50 and £5.75 plus a few tools to do it and carriage.............. think you might get the drift!!

 

[Keithj]

One square metre? The perfect size to practice on! If it doesn't work out right first time (which it will, if you follow the destructions) just knock it off and start again.

I've spent all afternoon lime filling and limewashing - neither of which I'd ever done, four years ago. They are essential skills if you live in a period property!

 

[Zebra]

I agree with the general drift of this thread! I'd never lime plastered (or plastered at all) before I bought this house, but I'm in the middle of doing my entire bedroom. It's not that difficult, but yes, does need doing over several days, as it needs "tending" - spraying, floating etc, over a couple of days after it's been applied. A joy to do though.
In the first instance, however, once the house is yours, why not just remove the cement render carefully, with a hammer and chisel, and allow the wall to dry before you apply any new plaster at all. That way, you'll be able to check that there isn't damp coming into the wall from a particular source, which needs addressing before re-plastering.
This may not help you much at the stage where you're still trying to find out what is wrong with the house before you commit to buy, or if you're in negotiations with the sellers. But that's perhaps the way it goes with old houses - there will always be unexpected finds, both good and bad....

 

[JHD]

You've persuaded me. I'll sign myself up for a course and do it myself. I'll post photos when we're finally in the house so you can see how I get on!

 

[tobydog]

JHD - you say you have 1 sq. m to repair, however, I have a horrible feeling you might find you have quite a bit more. You are lucky that the damp is showing itself in the area you plan to work on. I took my cement off after realising I could poke a knife blade between the cemented plinth and the sole plate in one corner. When I attacked other areas I found that the cement was attached half way up the sole plate and that there was void of damp crumbling bricks and composting oak below. No sign of damp decause the cement was masking it. The surveyor picked up totally unrelated areas in brickwork but was hopeless with the sole plate. After a dispute I received a full refund of my £700 survey fee and I've come nowhere near spending that yet and I've done one room.

I did find by the time I attended my basic course that I knew, in theory, quite a bit of what I was being told. What I got most out of the course was finding the confidence of putting that theory into practice. You can get endless information by Googling but I tried avoiding getting too bogged down with the science.

Pictures of your project would be good.