Lime Render Options

[dormouse]

The outside of the 1890 Victorian Semi I am hoping to buy needs rerendering as it is allowing ingress of water and has been badly patched. Plasterer with lime experience (so his blurb says) suggests we would be mad to want a lime render. He has suggested the following two options:

1. re-render in sand/cement/lime/waterproofer
2. ''mono couche'' render - ''Repois'' from a Spanish company called TEAIS, which he says is colour fast, water-proof, will not crack, discolour or suffer mildew.

Does this sound right? Unless I've misunderstood, this seems to contrast starkly with the 'pro-lime' sentiment on here.

 

[biffvernon]

'Plasterer with lime experience' or 'Plasterer with lime expertise'?

 

[Gervase]

Option one will be fine for a few years, but it will crack and will make the damp problem worse.
Option two will cost you more and will give you exactly the same problems - monocouche render is simply a fine cementitious render with colourant added to it that you apply in one coat.
Both are waterproof and will not allow the fabric of the building to breathe. Thus, when they crack, water will be trapped behind the render.
I would ignore the plasterer 'with lime experience' and find a plasterer who actually uses lime. Whereabouts are you?

 

[dormouse]

I've just looked it up and the exact word was 'specialist in lime plaster', suggests a cut above experience or expertise....

I'm in North/East Kent.

 

[thiambal]

This is from the Seeking Specialist section of this site

J H Upton & Son, 189 London Road, Temple Ewell, Dover, Kent, CT16 3DG
Telephone: 01304 823540, Fax: 01304 825456
Primary Supply: Plasterwork - Fibrous and lime plasterwork specialists


1 would imagine such a niche specialist would be willing to travel to the other side of the county - worth a try.

 

[NT]

Why not diy, tis not hard.

NT

 

[Penners]

Why not diy

...but not while there's any risk of frost.

 

[electricianid]

My 1890's end terrace is caked in nasty tyrolean sand/cement render.I know that restoring to original brick finish is not practical due to brick damage during any render removal. Replacing with lime render subsequent to removal of the existing render would be very nice, but the costs/time involved preclude this for the forseeable future (years). On discussing this quandry with my builder (who is renowned for undertaking lots of 'traditional' work lime,timber frame etc) he came up with this suggestion.
Fix any existing cracks, by opening them up with some type of power tool I assume and then filling the gap with sand/cement, and then render over the top of the house with another (smooth) coat of, I presume, cement render.
I immediatley brought up the obvious concern of the lack of breathability, but he assures me that since I have removed all gypsum/cement from the interior (to be plastered with lime) that this will be sufficient, as any moisture will simply be breathed away inside.
I cannot imagine it would make matters worse as the existing cement render (cracks aside) makes the wall impermeable now anyway, another coat would'nt make it any more so, plus the cracks would be repaired.Is there any reason why the new render would crack? Perhaps after >100years there won't be anymore structural movement (fingers crossed), indoor RH not a concern as there will be a heat recovery system fitted, it all seems to come down to - will one side of the wall be sufficient to expell all of the damp in the wall? After all if the render is crack free, there should'nt (theoretically) be any moisture ingress anyway.
I have read lot's of the related threads here but I have not seen this particular method discussed. I could really do with some of your opinions, bearing in mind that to do the 'right thing' i.e. replace with lime is simply not an option for many years yet.

 

[Gervase]

If your house is built on rock, has a reinforced concrte raft foundation or fairly massive wall foundations then further movement is unlikely.
However very few houses pre 1914 fit that bill, and the rest are moving slightly all the time to accommodate seasonal changes in the moisture content of the soil.
As such, cracking of cement render is pretty well unavoidable. What you need to do is to weigh up the respective costs - re-rendering (or patching and repainting) every 10 years or so, or putting on a breathable render now and merely having to worry about its decorative finish every few years.
Your builder has a point about the interior of the house encouraging 'breathability' bit it's a two-way street, and ideally you need the external skin to be as permeable to air and water vapour.
However, I appreciate that it's a matter of what your budget can stand. It may be worth getting some estimates for lime rendering; it may not be as exorbitant as you fear.

 

[NT]

If the wall isnt damp, and you xpect better finances some time in the future, this sounds like the sort of thing you can patch quickly now and leave it for a few years before doing it all properly. I'm not sure I'd want to waste time & money putting nother coat of render on though, its all going to fall off sooner or later anyway.


NT

 

[BMcD]

electricianid wrote:

Fix any existing cracks, by opening them up with some type of power tool I assume and then filling the gap with sand/cement, and then render over the top of the house with another (smooth) coat of, I presume, cement render.

If you're contemplating re-rendering the house with cement, I can't see it being that much more expensive to use lime especialy if you hack the old render off yourself but if the finances simply don't allow just yet then perhaps you ought to just fill the cracks in the mean time and forget about the cement re-render and use the money saved to get lime rendering done that much sooner

 

[BMcD]

Dormouse
I think you ought to find yourself another plasterer such as that suggested by thiambal. He is also an associate of The Woshipful Company of Plaisterers

http://www.plaistererslivery.co.uk/plr/indexe7c4.html?/plr/trade/

You should also find others on that link and if your original chap is there (which I doubt very much) then report him to the Master

 

[andrew gayton]

is the walling cavity construction? - could well be by this time...... a building of this age could also have used opc + gypsum (and many other materials such as keenes, roman, martins, selenitic or parian cement/s)..... so, if the walling is cavity........ this could dictate that a less permeable option could be ok......... think of all the cavity walled terraces with oil based mastic stucco over compo render coats..........

 

[Penners]

keenes, roman, martins, selenitic or parian cement/s

Andrew - for the ignorami among us (and I'm probably top of that class) could you give a brief explanation of those terms, please?

 

[andrew gayton]

the 18th and 19th centuries saw the production and patenting of numerous cements and artificial stone's (coade stone for example) at a time when spec. building was rife due to mass expansion through industrialism; this, coupled with the desire for neo-classical, gothic and other forms of revival motifs, on relatively humble buildings, all influenced the production of cements which were quick and easy to use for a variety of jobs from stucco work, often in quite deep relief, and run moulding etc. such materials were often used over a rough brick backing to simulate much more expensive material, scagliola (plaster coloured with limestone or marble) was used to imitate true marble - actualy looks quite good once polished with linseed oil.

 

[dormouse]

Not sure I'm brave enough to DIY, NT!

Thanks for the tip BMcD. As you suspected the plasterer I found is not a member. The one recommended by Thiambal is, so I think they'll be getting a call once/if the move is sorted. Thanks all for your help.

 

[Penners]

the 18th and 19th centuries saw the production and patenting of numerous cements and artificial stone's (coade stone for example) at a time when spec. building was rife due to mass expansion through industrialism; this, coupled with the desire for neo-classical, gothic and other forms of revival motifs, on relatively humble buildings, all influenced the production of cements which were quick and easy to use for a variety of jobs from stucco work, often in quite deep relief, and run moulding etc. such materials were often used over a rough brick backing to simulate much more expensive material, scagliola (plaster coloured with limestone or marble) was used to imitate true marble - actualy looks quite good once polished with linseed oil.

Very interesting - many thanks.

 

[Nemesis]

There are scagliola columns in the library at Melford.

Many a fine marble column in a stately is in reality a fake...


http://www.nationaltrust.org.uk/main/w-vh/w-visits/w-findaplace/w-melfordhall/w-melfordhall-the_hall/w-melfordhall-the_hall-highlights-ground.htm

 

[Penners]

Melford

Melford Hall is only 15 minutes from us, but I confess I've never been there. Probably because some friends went once and said they found it disappointing. I shouldn't be so easily swayed, should I?

My favourite house in that area is Kentwell Hall. A classic Tudor mansion rescued from crumbling ruin by Patrick and Judith Phillips, who have raised huge sums for the house with their annual Tudor recreations.

Have your friends still got a tea room in Long Melford?