Advice required - Render / Pointing / Painting

[lordgaz]

Hi All,
I am pleased to be making my fisrt post in your forum - There seems to be some very good advice being handled here.

Ok, some facts about my property -

Grade II listed Thatch - Timber Frame with brick infill - c.1620
One thatched extension (timber frame on red brick base) c 1920 or earlier (1st extension)
One thatched extension (rendered breeze block to look "real") c 1950/60


The front of the property seems to have had work at some time or another - the front of the bulding (apart from first extension) is set on concrete blocks (so probably done at time of second extension and before the listing.

The rear of the property seems to be just set on rendereded rocks and bricks

My first question -

The first extension is very tired - the render has fallen from the red brick work which supports the frame and the bricks seem more pointed with mud and debris rather than mortar - . I should really have come here firstly, but last weekend I bought some NHL 3.5 lime and some sharp sand. I asked a builder who renovates a lot of farm properties etc what mix to do, and he suggested 5 sand / 1 lime / 1 cement -(lime to help it breath, and cement to help it set) and it should be ok - Now having read more, I am really worried that I have messed this up - Do I need to rip with all off and do it again with Lime / Sharp sand - and should I point first, and then leave for an age to dry before adding a render (either of 5/1/1 (sand/lime/cement) or 2.5/1 (sand/lime) -
I know there is a lot of opinion about this (having read a few posts here) , not least from a conservation point of view, but also from a longevity point of view . Help -

Second question -
The old man we bought the cottage from seemed to do a lot of tinkering with the cottage and seems to have painted the outside beams in a mixture of a weathershielld type black paint and a bituminous paint - (from the cans inherited)
The white parts seem to be a weathershield type paint also (direct onto brick, and also onto "blown" plaster over brick). Where black paint/bituminous paint was added around the base of the house is where most render cover has been eroded / lost.
What is the best course of action here - strip / remove / live with?
Also, what would be the suitable treatment/paint for the black wood, and should it be limewashfor the white panels -

Sorry for the length.

G

 

[hoppy]

Sand & Lime render mixes :


1st coat = 3 sharpe/corse sand - 1 lime
2nd coat = 2.5 sharpe/corse sand - 1 lime
3rd coat = 1.5 playpit sand - 1 lime.

 

[Jon Maine]

You can render and point with nhl3.5 3-1 with good gritty sharp sand like flooring grit

Ideally you should strip the paint at some point. I would see about hiring a Doff steam cleaner a specialist tool for the job,You may find you have to finish with a poultice paint stripper.

As for returning to black and white, you will be using a 19th century paint scheme, if you want it to look period of original build lime wash the whole lot beams and all the same colour and it will be beautiful.

 

[Hatster]

Don't forget that you'll need to run your proposed changes (not your repairs) past your conservation officer to get listed building consent.

I recommend going on the SPAB's homeowner weekend courses - well worth the money!

And I agree with Jon (have to, as he's given me such good advice on my gutters 8) ) - limewash all over beams and panels looks wonderful.

 

[lordgaz]

Thank you very much for the helpful advice!
For my mix 1 lime / 1 cement / 5 sharp/coarse sand - Should I remove it all and re-point with 3:1 sand/lime? (I think it is still drying!)

Is it going to ruin my red bricks if I leave it?

Also, if I render with lime/sharp, with what should it be painted with (the previous render skirt around the house was once black colour (probably the bituminous paint)

Many thanks
G

 

[Schoolmarm]

There was some research done and I can't find a link. It said that mixing lime and OPC made it the worst of both worlds. It didn't set properly and it wasn't breathable or flexible.

How big an area have you done?



If you want it black there is a black limewash.

 

[Lime]

Thank you very much for the helpful advice!
For my mix 1 lime / 1 cement / 5 sharp/coarse sand - Should I remove it all and re-point with 3:1 sand/lime? (I think it is still drying!)

Is it going to ruin my red bricks if I leave it?

Also, if I render with lime/sharp, with what should it be painted with (the previous render skirt around the house was once black colour (probably the bituminous paint)

Many thanks
G

The mix you quote is a cement mix using lime as a plasticiser, I would not describe this as lime mortar whatsoever.
It is hardening by the minute.
If you do want to remove it the sooner the better.
Tomorrow it will be much harder than today.
Damage to bricks?
Almost certainly.

With reference to adding cement in a small proportion to a lime mortar it has been found that it does fail faster than just plain lime mortar.
Cracks appear.

 

[Gervase]

Wot lime said with bells on.
On no account use cement in the render. It will crack, as sure as eggs are eggs, and it will trap water, saturating and degrading the bricks beneath. Modern cement renders are fine for modern cavity blockwork built onto a massive concrete foundation or raft, where there will be no seasonal movement, but they are utterly inappropriate for single-skin brickwork or for any walls without modern foundations.
And, even on a modern house, the render will eventually crack. Umpteen coats of non-breathable paint and waterproofing will probably disguise that, but such treatments should never be used where the fabric has to remain breathable.

 

[lordgaz]

Thanks again for the replies -
I have been away all week with work and have not been able to think of anything else - I have not had chance to remove this cement based mix

previously I pointed the bricks and then did a skim all over bricks - the skim is dry, but the pointing may still have a wee bit of wetness

am I going to do more harm than good if the cement is pretty dried fast onto the bricks and I try to remove?

 

[Lime]

I'd be out there taking it off.

 

[Gervase]

As the bishop said to the actress, "Gerremoff!"

 

[lordgaz]

Thanks - I have been out all evening removing the worst of it - It was like concrete! I get the point.

will have to drill out the pointing (fill it with holes) before chisel otherwise I think a fair bit on damage will be caused to the bricks if I just bash it out.

I feel a bit happier now - thanks for the advice. I am sure I will be back for some more at some point

BTW - how / where do I get hold of or make black limewash? did a bit of googling, but could not find a black version.....

 

[Schoolmarm]

http://www.periodpropertyshop.co.uk/acatalog/Lime_Washes_and_Lime_Paints.html



third row of paint down.

I don't know how black it is.