Help!! Damp plaster falling off

[glennhudsonuk]

Just bought a house that is 160 years old. the gable end brick wall has been rendered externally and there is an injected damp proof. Internally, the wall has been covered with cladding for decades!

So basically they damp proofed the outside but did nothing to eradicate the problem inside. Just left it, as it was hidden anyway it was deemed not a problem i suppose.

The bricks actually look and feel damp low down on the wall.

There is no ventilation or heating in the hall (where the wall is). would having a radiator put in there help to keep it dry and would it be an idea to get a de humidifier in before plastering?

I have taken all the cladding off and the plaster is falling off the wall in places, others it is not too bad. the top half plaster has cracked and is bulging in places.

I am thinking the best way forward is probably to take all the plaster off and start again.

should the damp still be an issue as there has been work done externally?
have left a fan heater in there for a day just to make sure it is dry
should i then render with a normal sand/cement mix?
how many coats and how thick should each coat be?
should i use a special plaster?
Can i dot and dab?

 

[peaps]

Just bought a house that is 160 years old. the gable end brick wall has been rendered externally and there is an injected damp proof. Internally, the wall has been covered with cladding for decades!

So basically they damp proofed the outside but did nothing to eradicate the problem inside. Just left it, as it was hidden anyway it was deemed not a problem i suppose.

The bricks actually look and feel damp low down on the wall.

There is no ventilation or heating in the hall (where the wall is). would having a radiator put in there help to keep it dry and would it be an idea to get a de humidifier in before plastering?

I have taken all the cladding off and the plaster is falling off the wall in places, others it is not too bad. the top half plaster has cracked and is bulging in places.

I am thinking the best way forward is probably to take all the plaster off and start again.

should the damp still be an issue as there has been work done externally?
have left a fan heater in there for a day just to make sure it is dry
should i then render with a normal sand/cement mix?
how many coats and how thick should each coat be?
should i use a special plaster?
Can i dot and dab?

Is the wall a cavity wall and is the plaster and mortar lime based. I suspect you have problems due to the injection and cladding.

 

[glennhudsonuk]

not cavity wall, the house is 160 years old. not new plaster so lime based/mortar. i have found what appears to be a bricked up door where the plaster coming off is worse. everywhere else is pretty firm but damp at the bottom. it has a waxy feel when touched and the bricks look darker and I am presuming this is because of damp

 

[peaps]

not cavity wall, the house is 160 years old. not new plaster so lime based/mortar. i have found what appears to be a bricked up door where the plaster coming off is worse. everywhere else is pretty firm but damp at the bottom. it has a waxy feel when touched and the bricks look darker and I am presuming this is because of damp

Yes I would have expected it to be a solid wall but you have to ask. Without having a look at the problem it's hard to advise in this situation. Could you post some pictures? My felling is that it's the cladding on the outside of the wall that's causing the problem with damp. But first you could go around and do some checks to eliminate other possible problems. Is the guttering sound, down pipes, drains etc. If everything is ok then you need to look at the cladding IMO The house was designed to breath, in other words, the lime would take in moisture and naturally evaporate but if you seal the wall the moisture stays in the wall and you are faced with damp problems. The damp proof injection would not be a good idea also.

Let's see if you can load some pictures. I'm shooting up the M1 at the weekend and my be able to do a detour and have a look..

 

[glennhudsonuk]

The cladding is on the inside. i have read that damp proof injections are not good for old houses but it is done now. I think I'm inclined to agree with the fact that the wall has not been allowed to breathe due to the cladding ( which incidentally then had thin hardboard nailed to it.

on removing the plaster I found that there used to be a door which has been bricked up and plastered over. ( before the damp treatment )

I have had all of this plaster off as it was bulging and coming loose anyway. in fact I've taken about 40% of the plaster off and was thinking I might as well take the rest off.

So do you think a dehumidifier is a good idea to start with?

Also, the wooden floorboards feel a bit damp near the wall.

It is in a tight hall way so cannot get a decent pic.

Good of you to offer to come and take a look but I wont be around until sunday eve.

 

[huddsspread]

if it was my house, take all the old rubbish plaster off, then you can see what your working with, if its that old it should be easy. As for the de humidifier--yes get one, as lot of damp is condensation based.

 

[joe-90]

if it was my house, take all the old rubbish plaster off, then you can see what your working with, if its that old it should be easy. As for the de humidifier--yes get one, as lot of damp is condensation based.

This is dead true. A damp wall is fractionally colder than a dry one and attracts condensation - which makes it damper - which makes it colder ....

 

[glennhudsonuk]

Cheers for that lads. I'm getting one sorted.

Now on the subject of what to do next. was going to render it with sand/cement and then get a plasterer in to finish.

What would you suggest is the best method once i'm back to brick and i've dried the wall out? Going to take it all off to ensure i get an even finish, its a bit all over the place.

 

[peaps]

Cheers for that lads. I'm getting one sorted.

Now on the subject of what to do next. was going to render it with sand/cement and then get a plasterer in to finish.

What would you suggest is the best method once i'm back to brick and i've dried the wall out? Going to take it all off to ensure i get an even finish, its a bit all over the place.

If you are going to render then you will need to do it in lime or you could go down the plasterboard insulate route, this will need a little thinking about as you need to make sure the wall breaths.

 

[dmplastering]

Cheers for that lads. I'm getting one sorted.

Now on the subject of what to do next. was going to render it with sand/cement and then get a plasterer in to finish.

What would you suggest is the best method once i'm back to brick and i've dried the wall out? Going to take it all off to ensure i get an even finish, its a bit all over the place.

You would struggle to find a plasterer to skim after a DIYer has rendered the wall themselves. I for one wouldn't do it unless it has been done perfect.
I would go down the plasterboard route myself as leaps suggested but in no damp expert so couldnt possibly say if this is the best method

 

[Richard C]

Now on the subject of what to do next. was going to render it with sand/cement and then get a plasterer in to finish.

You don’t want to be putting ordinary sand/cement render over solid external walls or you’ll likely have the same problem again before too long, either through penetrating damp or condensation. As already suggested, youe either need to go down the lime render/plaster route or best option would be for you to insulate with a damp membrane & line with plasterboard or use an insulated plaster board like Thermaline. I doubt I would take on skiming your DIY render base either!

Be careful if your having any building work inspected by LABC, if they spot or find out you’ve stripped back all the external walls, they’ll most likely make you upgrade to modern thermal insulations standards anyway.

 

[peaps]

Be careful if your having any building work inspected by LABC, if they spot or find out you’ve stripped back all the external walls, they’ll most likely make you upgrade to modern thermal insulations standards anyway.

http://www.lime-green.co.uk/catalogue.php?Plv=1&Pid=&Cid=10&Clv=2?

 

[glennhudsonuk]

I didn't really have much choice taking the plaster off as it was falling off anyway.

would any plasterer be happy to use these lime based plasters?

If I was to go down the route of insulating boarding it what membrane would i use and would this go underneath the wooden battens?

money is tight so am looking for cost effective as well as it doing the job.

 

[glennhudsonuk]

can't see a forum on here that deals with damp problems, is there one?

 

[Richard C]

would any plasterer be happy to use these lime based plasters?

No & don’t believe what some may tell you. You need someone who is experienced with the material & they will be few & far between amongst the dross of skimmers who pass themselves off as plasterers. A “heritage” accredited plasterer would fit the bill but when you find one, they won’t be cheap!

If I was to go down the route of insulating boarding it what membrane would i use and would this go underneath the wooden battens?

Membrane under the battens but I would go for an insulating board with an integral moisture barrier such as “Thermaline Plus”; no battens & no membrane necessary.

money is tight so am looking for cost effective as well as it doing the job.

Cost is of little relevance; you either do the job properly & pay once or bodge it for half the price & then do it again in a few years time which maybe less than you might think!

can't see a forum on here that deals with damp problems, is there one?

They are here already, either in Building or Plastering; posting in either should get a response.