There is plenty of information out there on render mix, but its all very complicated

I have had a good quote (not the cheapest) on rendering two cotswold stone internal walls (property circa 1870).

The plasterer suggested using BAL APD to prime, and then a lime, cement, sand mix for the render.

I was concerned with the use of cement in the mix... is this justified?

He did say he can use a lime mortar, but this would put the price up considerably.

Any thoughts chaps?

He's probably thinking of a 6: 1: 1 sand,cement,lime mix or similar.

I have used 3:1 or 4:1 sand/cement mix with a touch of lime in the past, Lucious who is on here, reckoned that was far too much cement, I think he's right on this.

Your builder is using hydrated lime, one assumes, not the old style lime, that needs to be worked (Hydraulic). Hydrated lime will need cement for the mix to set.

Using the lime morter is the traditional way of doing it, that would require the hydraulic lime.

Assuming I haven't got the terminology mixed up.....

Originally Posted by cornish_crofter

He's probably thinking of a 6: 1: 1 sand,cement,lime mix or similar.

I have used 3:1 or 4:1 sand/cement mix with a touch of lime in the past, Lucious who is on here, reckoned that was far too much cement, I think he's right on this.

Your builder is using hydrated lime, one assumes, not the old style lime, that needs to be worked (Hydraulic). Hydrated lime will need cement for the mix to set.

Using the lime morter is the traditional way of doing it, that would require the hydraulic lime.

Assuming I haven't got the terminology mixed up.....

That makes sense.

Any there any real drawbacks to using the new method of hydrated lime and cement?

Finally, am I ok to tile with travertine on this

I just happened on this thread...
19th century buildings used lime plaster, WITHOUT any cement. Old materials are not necessarily compatible with modern ones, and cement has proven to be very damaging to old properties.
Your walls shouldn't be primed; the plaster mix used should consist of lime putty with graded aggregate, and hair. You can mix this yourself, but it's more usual to buy it ready-mixed in tubs. It will take longer to cure but it'll last far longer than cement (and it smells much nicer as it dries!).
There's no reason why it should cost substantially more than modern render. The only difference is in the preparation and aftercare; the application technique is very similar.
Basically, if you're in an old property, don't allow any cement near your walls!
Here are some links to check out:
The Lime Centre
Mike Wye & Associates.
The Old House Store
Amir

from my experiance the render should not be stronger than the backround ie little or no cement content (sounds like quote should be cheaper ) finding good solid plasteres to do the job with experiance and knoledge of working with lack of cement in render (this makes the quote dearer) if your render is stronger than walls tends to sheer the face off wall hope this helps