External Gables To point in Lime or to render in cement?

[Hiriaeth]

Hi all,

I really need some quick advise as my insurers are pressuring me for a reply and they have started hacking off so need to make a decision...Hate those!

My House is a small welsh farmhouse built around 1860 using local stone which is a hard volcanic stone and totally impervious to water. The property was pebbledashed in around 1980. The House is at 1000 feet overlooking the Irish sea and recieves high rainfall and very strong winds with regularity! A Year ago storms damaged the chimneys and has led to water ingress on both gable ends, the cement pebbledash is in very poor condition.After a year of battling insurers they have now decided correctly to remove the render. The stonework underneath is mixed rubble and large stones with lime mortar pointing.

I have two options. Either I can re render the gable walls in a flat cement render and paint or I can have the walls pointed up.

My feeling is to return the property to a more traditional finish. I also have no idea if the property was originally pointed or rendered.

Problem-
If I point in lime my concern is that it will not stand up to the prevailing weather conditions here. I also feel that cement would look awful as a pointing. I have defintely decided that the west facing gable will be cement rendered as it is so exposed As a matter of interest my North facing wall has been hacked off and left unpointed for 2 years now with no ingress of water moisture readings on this wall internally show it to be very dry.

The [problem I have is what to do with the East facing gable. This is more sheltered but gets less air circulation and sun than elsewhere so tends to take longer to dry after rain. Winters here can be very hard last year we had 8 weeks of rain and wind every day. Do you feel Lime would be suitable in these conditions? If so what mix? Non Hydraulic or NHL Mix? I also Have to do this work now as in the next few weeks so not ideal weather wise. Or would I be better just accepting that the weather here is so awful that cement render is the only thing to be recommended. The Interior of the house has been re plastered using lime plaster this was done last year, I do not know if this would affect the choice for the exterior.
Any advice would be most welcome.
Many Thanks
Hiri

 

[biffvernon]

Do NOT use cement.
At all.
Anywhere on your house.
Complete no-brainer.

Now we can get on with debating whether in your particular case there is reason to use a hydraulic lime. I probably wouldn't, thinking that hydrated lime render has stood the test of time on many an exposed hillside.

 

[MdB]

Use lime but don't put it on if there is a chance of frost. NO cement.

 

[Tom]

Cement? No, no, no, no, no!!!!! PLEASE don't use it :shock:


Jaqy

 

[worms]

I'm acquainted with a building in a similar coastal situation where the southern gable (sea to north gable) stays damp through the winter since the sun angle is too low to reach the wall. At some stage it was repointed with cement and it is now a classic case of the cement pointing still being in place but the stones in between have been badly eroded - even ones which to my untrained eye would appear to be granite.

My thoughts are that a lime harl is called for, but I am no expert.

 

[Gervase]

Harling or roughcast is what was traditionally used in Wales on exposed surfaces. Render with a moderately hydraulic lime and then, before the set is complete, make a slurry of hydraulic lime and rough stuff (you want aggregate a bit smaller than pea gravel - about 6-8mm - and hurl that against the render. It's a messy business, but gives and authentic and effective finish.
Dont' use cement.

 

[Cloudscape]

My house has some roughcast that I need to restore in a couple of places. I have wondered what it was composed of.

One of the locals has family connections going way back, and I've been told that they used 'hot mortar'. What does this mean?

 

[biffvernon]

They added quicklime to water, which generates a lot of heat, and then applied the resulting hydrated lime before it cooled down. It is the more exiting end of mortar mixing.

 

[Hiriaeth]

Thanks to everyone for the useful advise. I have recently spoken to two seperate lime plasterers one of whom is also a supplier. They both recommend as a render a mix of 5 Parts Sand (Local Quarry) to 2 Parts NHL 3.5 for two scratch coats and to finish off with a coat 3 Parts sand to 1 part NHL 3.5 with either a sponged or a hurled finish.
To Point they recommended the same mix pointed flush to the stonework.
They also pointed out that none of this work should be undertaken now as the mix will not set at all below 5 degrees and frost will ruin it. Whilst between 5 and 10 degrees the mix would still take twice as long to dry out.
My prob here is time , wind and rain. My very exposed wall would be impossible to protect with tarpaulin or hessian (It would never stay on) whilst the mix goes off. I am contemplating leaving the more sheltered wall until the spring when this work can be done in better temperatrures. The exposed wall cannot wait as I will just end up with water ingress in two bedrooms and the sitting room which all share this gable wall. Sadly this one wall may have to be cement rendered.

Unless of course anyone has any other bright ideas
Thanks Hiri

 

[Andrew Bodenham]

If you cement render the wall now you'll just be setting up problems for the future. You know it's the wrong solution. The real problem now is how to give some weather protection to the wall for the winter so that you can have it lime rendered come the spring.

But first, have you considered leaving the wall unrendered and simply pointing it up. You mention that your North-facing wall is not even pointed but is essentially dry. Are you worrying about a problem that doesn't exist? My own rubble stone gable gets a fair amount of sea-blast and rain and copes pretty well. It was rendered once (cement), but thankfully this was removed by a previous owner.

If you really find a need to cover up then why not cover the gable with tarpaulin for the winter. This can be secured by screwing 2"x1" battens over it at, say, 500mm spacing. Quite a bit of work to rig up, but relatively cheap and it will allow you to do a proper rendering job later. (Rather than having to hack off your new cement render a couple of years from now when it's cracked and parting company with the wall. )

Or perhaps you could erect a scaffolding framework against the wall and use that to support tarps.

Be assured that having read a few posts on this forum you will know much more about the right way to treat your old house than your insurance company. If they won't play ball you may need to get an independent surveyor to back up your lime-based approach.

 

[biffvernon]

Sadly this one wall may have to be cement rendered.

:evil:No!:evil:

If there's any seriously big holes that let the water in, stuff some lime mortar in, if only as a temporary measure. Then do a proper job in the spring. A little winter damp will do far less harm and will be only temporary. Stick cement on it and you've given yourself a big problem for years.

 

[Lady_Mari]

We have used sheets of ply as a temporary measure to keep rain off our exposed damaged wall over the winter until we can lime render properly. It is also a lot quieter than plastic & won't blow away.

 

[Hiriaeth]

Thanks again for all the excellent advice , really helpful. I am of course only guessing that I may get water penetration over the winter, as you suggest I may not! I had already considered taurpaulin but had decided that it wouldnt stand a chance up here but hadn't thought about using ply so that may be worth looking into. I just have to convince my insurance company to leave me with the scaffolding and then I can work at cleaning and preping the area so it is ready for spring. The Insurers will of course only pay to return the wall to as it was before ie cement render. I am paying the difference for the lime work/pointing. Luckily the surveyor for the builders supplied by the insurers has agreed that lime is the best option so that may hold a bit of sway. Together with the fact that it has taken me a year to get them to do anything. It is suprising how quickly minds change when Insurance ombudsmen are mentioned! Having spent time and money removing all the cement plaster inside and re lime plastering the whole house it would indeed be slightly odd not to finish off the job.

Oh by the way can anyone recommend Lime plasterers who work in North Wales/Gwynedd who would be willing to quote for the work and maybe I can get the insurers builders to sub the work out to someone who knows what they are doing.

Also on a completely different subject I am replacing all the UPVC windows and rather fancied wooden sashes again. Can anyone recommend an excellent reliable company/joiner? Any thoughts on windows most gratefully recieved.

Thanks again