Internal Lyme Render

[Hairybear]

Another schoolboy question coming I suppose, maybe.

Priced up a 1st floor bedroom in a house this week, 200 yr old terrace with solid (non cavity) brick and stone walls. All internal walls are timber so a simple re-board and top coat.... No snags.

Now, part of the job is to re-float the external wall however Ive priced up using hardwall.....don't shoot me yet!

The customer has queried this, I suppose rightly however the outside is rendered with sand cement, as is the room below with no signs of damp.....

Hes now giving it the 'the wall needs Lyme render cus it needs to breath, I've read it on the internet', which is a fair point however, I asked him if he'd be painting the wall with a modern paint, which he will be which surely negates the whole point of applying a Lyme render in the first place????

What are your thoughts gents? I ain't got much experience in Lyme rendering so pls explain any buzz words if you use em!!!!!

cheers.

 

[stokeplasterer]

If you do use a lime plaster inside and use modern paint it can't breathe so there's no point putting it on ! And if the the render is sand and cement with or with out modern paint it can't breathe any way so there's no point putting it on ? Best thing to do would be to get better ventilation in the room and dry line it so you get a thermal break ( a gap ) keep the boards one inch off the floor and don't do a solid dab on the skirting line this will help to give air circulation behind the dry lining or use a thermaline super with four mechanical fixings this will give a barrier against the damp. But I think more ventilation for the room would be best.

 

[bodders13]

If the guy is adamant that you have to use Lime then use Lime. Obviously they will be an increase in the price for labour and materials but that is to be expected. Where you get the lime from just ask for a paint card of some breathable paints. At least you have tried to make your work breathable then. There isn't really much point in using Lime in this instance if it's not going to get the proper treatment, ie wrong paint as well as the external wall already having S and C.

 

[Hairybear]

That's the problem with the internet I suppose. He's seen somewhere that Lyme is the only solution and to tell his 'builder' to sling his hook if he suggests anything else. What the net fails to do is explain the reasons Lyme is used and importantly, the other factors which need to be taken into account.....

 

[xyzplasterer]

No point using lime if as you say...give him the price that will put him off if it doesn't happy days for you.