navitron
 
Renewable Energy and Sustainability Forum
Welcome, Guest. Please login or register.

Login with username, password and session length
News: Anyone wishing to register as a new member on the forum is strongly recommended to use a "proper" email address. Following continuous spam/hack attempts on the forum, "disposable" email addresses like Gmail, Yahoo and Hotmail tend to be viewed with suspicion, and the application rejected if there is any doubt whatsoever
 
Recent Articles: Navitron Partners With Solax to Help Create A More Sustainable Future | Navitron Calls for Increased Carbon Footprint Reduction In Light of Earth Overshoot Day | A plea from The David School - Issue 18
   Home   Help Search Login Register  
Pages: [1]   Go Down
  Print  
Author Topic: Ideas for a blowing plaster on an internal wall  (Read 9332 times)
Other-Power
Hero Member
*****
Offline Offline

Posts: 1288


« on: September 27, 2012, 05:20:38 PM »

Hi all,

I have done a bit of work on my house to insulate internaly using Kingspan board and steel track and stud.

My sister lives in a soild wall house also and has had trouble with plaster growing salts that push off the paint and once through grow rapidly.  She has used sealer, special stuff that is two part in two colours so you can see its done fully.  This stuff has work ok but the salts have started to push through again. 

We are not sure why the problem occurs, I think that its condensation that forms on the walls and combined with heat causes the salts to form.  My sister and I have talked about dry linning the wall but as we are not sure if the salts will grow again we need to use an insulation that can compress, such as rock wall/fibre glass.  I am not keen on this as I think that the rock wall insulation will absorb water in time and sag.

Does any one have thoughts on how this might work and if damp may form in time?

Cheers

Jon
Logged

My advice is based on me spending my money doing this and my job spending others money doing this.
Ivan
Hero Member
*****
Offline Offline

Posts: 2262


« Reply #1 on: September 27, 2012, 05:37:29 PM »

My Dad has the same problem. He tried some special product supposed to cure the problem but it didn't. I think the problem is often caused by non-breathable render on the outside of the property. Someone from Cadw told me that render on old solid wall properties should be lime based to solve this problem, but usually builders don't realise and put little or no lime in the mix.

Dad's solution is to dry line, using foil-backed plasterboard. He's going to put PU insulation behind it, but not to solve the problem - just to make the room warmer. The insulation and the foil should hopefully reduce the evaporation rate. The salts will still efflorrese, but won't be visible.
Logged

www.epogee.co.uk - Solar PV & Solar Thermal Training / MCS
Other-Power
Hero Member
*****
Offline Offline

Posts: 1288


« Reply #2 on: September 27, 2012, 08:11:54 PM »

Ok Ivan,

Glad im not the only one here, we where going to use vapour board and make a good seal, my sister does not want to have the insulation away from the wall as it will take up a lot of space.  We cant use solid insulation as the salts would push the insulation and that would push the board, or am i over thinking the power of salt growth?

Cheers

Jon
Logged

My advice is based on me spending my money doing this and my job spending others money doing this.
Bodidly
Hero Member
*****
Offline Offline

Posts: 1559



« Reply #3 on: September 27, 2012, 08:41:18 PM »

I have spent most of my life in a house with this kind of problem.
 It is very hard to tell if you have rising damp external damp or condensation. We tried many paint on solutions but none of them worked. As said above it is important to let any moisture in the wall out, this could be inside or outside. Most of the problems we had were caused by condensation and this can be resolved with insulation inside or outside. On my parents house I resolved this problem with external insulation, tearing of the internal render and lime pointing the stone work in the downstairs room were rising damp was also a problem and lime plastering the upstairs walls. In my sisters place I dry lined with celotex sealed to the wall and plasterboard fixed over the top. If you do use a lime plaster it is important to use a breathable paint with it.

These are only my experiences and your house may have a different reason for the problem.

Hope this helps
Beau
Logged
guydewdney
Hero Member
*****
Offline Offline

Posts: 4320



« Reply #4 on: September 28, 2012, 01:39:10 AM »

if its water ingress use K11 - any builders merchant will sell it - but it aint cheap.

salt can be from using the wrong sand - if theres any 'soft' sand in the mix, its from a beach usually - and thus salty.
Logged

Pic of wheel on day 1
7.2kW Waterwheel and 9.8kW PV
Other-Power
Hero Member
*****
Offline Offline

Posts: 1288


« Reply #5 on: September 28, 2012, 01:51:57 AM »

Hi again,

Yes, sand was mentioned, sure its not rising or penatrating damp.

Will removeing the heat and condensation stop the salts forming?

Cheers

Jon
Logged

My advice is based on me spending my money doing this and my job spending others money doing this.
jonesy
Hero Member
*****
Offline Offline

Posts: 849



« Reply #6 on: September 28, 2012, 02:01:34 PM »

I had a problem with blowing plaster and salts in a badly built 1970s extension.  The floor membrane had been deliberately tucked into the floor pour, meaning the damp foundations were bridged above the DPC.  Coupled with this, the external floor level was 100mm above DPC, rather than the normal 100mm below.  By recovering the floor membrane, lowering the outside level and waiting 9 months (9" wall - they dry at a rate of about 1"/month) I re-plastered to 1m with local sand/cement render. 
It's worth checking you don't have water leaking in at high level.  This will readily dribble through a solid wall and will pop out somewhere. A friend once tracked a leaky gutter on the 1st floor from the end of ground floor curtain pole, through to the lintel and up the inside of the wall.
Logged

1.1kWp PV & SB1700. 7kW log burner.
Other-Power
Hero Member
*****
Offline Offline

Posts: 1288


« Reply #7 on: September 28, 2012, 11:55:55 PM »

I will go up into the loft and have a look for leaks, it has been noted that her ridge tiles are not great and could do with being re set.  It is possible that there is a leak and it is running down the felt onto the walls.  The walls that are bolwing are on the ground level.

I think I need to investigate further rather than just covering up.

Watch this space!

Cheers

Jonathan
Logged

My advice is based on me spending my money doing this and my job spending others money doing this.
Ivan
Hero Member
*****
Offline Offline

Posts: 2262


« Reply #8 on: October 02, 2012, 09:20:49 AM »

If you do have rising damp and you don't have a damp course (common in old houses), then you can of course use an injectable damp course.
Logged

www.epogee.co.uk - Solar PV & Solar Thermal Training / MCS
Other-Power
Hero Member
*****
Offline Offline

Posts: 1288


« Reply #9 on: October 02, 2012, 10:50:50 AM »

It is an idea Ivan, thing is, there is no yellowing of any paint work inside or out so not suspecting rising damp, these patches are patches of salts.

Being a granite house, I have never believed that it would be possible to inject fully through one side to the other as the granite lumps are all different shapes and sizes and the 'course' of lime/cement/cob/strew, and who knows what else, is varying in depth to an unknown amount so simply using maths to work out the injection rate wont guarantee a good job.

I was going to have a look yesterday but still working on my house at the moment.

Will update when Ive had a look.

Cheers

Jon
Logged

My advice is based on me spending my money doing this and my job spending others money doing this.
MisterB
Jr. Member
**
Offline Offline

Posts: 72


« Reply #10 on: October 08, 2012, 10:48:33 PM »

I re-plastered to 1m with local sand/cement render. 

i have a small problem with rising damp, called in a plasterer (to do other work) he stated he normally just re-renders with sand/cement but uses a waterproofer additive. so if you do use sand/cement, make sure you add the waterproofer.

my solution, which has worked on previous houses WITH CAVITY WALLS (  i know the op doesnt have cavity walls)  is very labour intensive and takes a couple of weeks, is to ensure the cavities are not blocked with debris, which they normally are. i remove 2 or 3 bricks every couple of days, making sure i re install them properly, cleaning the cavity as i go.

for the OP i suggest eliminating one thing at a time doing the 'cheapest' options first, start with ensuring the outside is properly pointed or rendered to stop driving rain etc, ensure there is some sort of DP - if not then install one, either mechanically or chemically. i seem to remember one type going back a few years that was a series of copper strips, specifically for solid stone houses - all those can be done relatively cheaply if you are doing it yourself.

if it is condensation, then make sure there is an air flow and the room house is not sealed - you could even potentially consider an air conditioning system of some sort to extract the damp from the air. or as suggested it might be that its an issue with the type of plaster used and you may need a lime rendered surface inside the building, which allows the walls to 'breathe'
Logged
jonesy
Hero Member
*****
Offline Offline

Posts: 849



« Reply #11 on: October 09, 2012, 10:07:26 AM »

i have a small problem with rising damp, called in a plasterer (to do other work) he stated he normally just re-renders with sand/cement but uses a waterproofer additive. so if you do use sand/cement, make sure you add the waterproofer.

It's funny you should mention water proofer.  I have used it in the past replastering, but can't remember if I did on that occasion.  Here's a thought, could be obllox.  If the water is still present, but now held back at the brick due to the water proofer, if any cracks develop, the problem will re-occur?  Also, will the general dampness form into a larger mass and pool at the bottom of the wall?

Logged

1.1kWp PV & SB1700. 7kW log burner.
Other-Power
Hero Member
*****
Offline Offline

Posts: 1288


« Reply #12 on: October 09, 2012, 12:38:51 PM »

Just to add to the mix,

We have poked the mushy bits a bit more and it seems that the salts are growing on the surface of the plaster/render soft sandy stuff and not pushing the plaster off as I first thought.  With this in mind, are the salts being grown by the evaperation of the inside wall due to heating?  If this is the case then insulating the wall would seem to make sense, as this is a good solution to reduce condensation etc.

hmmmm.

cheers

Jon
Logged

My advice is based on me spending my money doing this and my job spending others money doing this.
Other-Power
Hero Member
*****
Offline Offline

Posts: 1288


« Reply #13 on: November 09, 2012, 01:45:51 PM »

Well to complete this thread.

We built up an 18mm steel stud wall infront of the old wall.

Hacked out the blowing patches and installed 10mm laminate/underfloor insulation and boarded over with mositure rated plaster board, the green stuff.

The salts will have to grow 8mm before they even get a chance to push against the insulation, I think it will keep the wall looking good for a good while.

Cost in all was about 150, stud frame, insulation, plaster board, filler, sand paper etc, plaster board sealer, paint and skirting for 8mx 2.3m with a window.  My sister was happy with this and the wall looks much better and no apparant lost of room space.

A small amount of insulation will make a little difference but the main aim was to remove the heat to help stop the salts from growing.

Cheers

Jon
Logged

My advice is based on me spending my money doing this and my job spending others money doing this.
Pages: [1]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.20 | SMF © 2013, Simple Machines
SMFAds for Free Forums
Simple Audio Video Embedder
Valid XHTML 1.0! Valid CSS!