Confused about plaster

MyNewVictorian

My partner and I bought our first home together: a solid red brick (seems no cavity) Victorian house built in 1895 in West Yorkshire.

Suffice to say we've been here 2 weeks and have had to do over £1500 worth of repair to gutters, roof, plumbing. Now we have to replace a lot of plaster on the walls and ceilings in several rooms because of damage from uncleaned gutters and a busted cold water tank int he loft (which was repaired, but the damage it caused ignored.)

At any rate, even if there hadn't been any damp damage, most of the rooms have the original plaster -mining castoff from the area, sand, and what looks like hay!- and they were probably past their prime?

I've been trying to do my due diligence and get 4-5 quotes and research the best materials for the job, but I seem to have stepped into the crossfires of a builder vs. conservationist war?

Basically, I've been reading that I need to let the house breath (which I take to mean vapour permeability in the least and some air permeability at most) and use lime plaster, no waterproof internal treatments.

Every tradesperson I've spoken to from modern damp companies has said this is a myth or an outright lie and recommended we install a water-proof membrane and use cement-based plaster over top of it instead.

Who is right? What do we do? Where can we turn to for real answers??? :huh::huh::huh:

Any advice and a point in the right direction to resources would be great. This is my first house and I'm terrified of committing an expensive and destructive error.

Also, should we install air bricks to ventilate the first and second floor suspended flooring?

stuart45

MyNewVictorian wrote: »

Every tradesperson I've spoken to from modern damp companies has said this is a myth or an outright lie and recommended we install a water-proof membrane and use cement-based plaster over top of it instead.

Unlikely to be a time served tradesman working for a modern damp company. Using a proper lime product would be a much better solution.

TELLIT01

If the plaster has bits in, it is almost certainly lime plaster, and is used on old buildings because it breathes. I don't know whether using conventional plaster over a waterproof membrane would cause problems or not.

FreeBear

MyNewVictorian wrote: »

Every tradesperson I've spoken to from modern damp companies has said this is a myth or an outright lie and recommended we install a water-proof membrane and use cement-based plaster over top of it instead.

They would say that because they are in the business of selling expensive "cures" and don't care about the long term damage. If anything, there is a vested interest in using inappropriate materials so that they can come back in 5-10 years time to flog more of the same.

Have a chat with the guys over at Wormersleys - They advertise lime products plus advice on their web site. Being up in the same neck of the woods, they should be familiar with the local architecture & historic building practices.

A general rule of thumb - If the property was built using lime, then use it for repairs. Modern cement & gypsum products are too inflexible for older properties.

MyNewVictorian

Thanks everyone for the advice! We're feeling a lot more confident about things about are sticking with like-for-like!

stillEuropean

There's an excellent website called Period Property which provides a wealth of information on using the right materials for old houses. I recommend it.