Old houses and Damp

[David Callister]

I am buying an old house and the garden is above the floor level on the gro0und floor along one wall. I have had a survey done and the surveyor recommend "tanking" these walls to aleviate any damp issues. Does anyone have any experience of tanknig, particularly costs

 

[thiambal]

I guess the standard answers/questions would be

1. Is there any evidence of damp currently (other than the surveyors meeting readings?)
2. Has any work be done in the past - if so what.
3. What will the room be used for?
4. If there an identifiable source of damp than can be remedied?
5. You probably need to live in the house for a while - keep the rooms well ventilated and see what happens through a few seasons and then make a decision.
6. Tanking probably best avoided in old houses.

Your best bet is to read through past posts on the subject of basement damp and if they do not answer the your questions post again here with more info.......

The someone who knows more than me (and I know nothing) will no doubt give some sensible suggestions.

 

[PC]

Hi David,

I would avoid traditional tanking at all costs will cause more problems in the long term.

Perhaps you might like to look at NT's posting NT's Damp FAQ Tread on this very subject, which he has taken the time and trouble to put to gether in response to your very question.

PC

 

[David Callister]

Many thanks, difficulty is that I do not yet own the house so dificult to establish full picture. Tanking definatley attempted in one room, still signs of damp would it be best to strip this wall? Other rooms affected are lounge, dining room, library/study. So all affected rooms will be in regular use

 

[middi]

David, from what you decribe, the first thing I would consider would be to build a retaining wall for the garden level and create an air gap of at least 2 feet around the wall of the house with good surface water drainage away from the house.

Make sure you go at least 6 inches below internal floor level.

The above is more important than the tanking as at present.

Keep an eye on things and take it one step at the time if you have to.

 

[NT]

If you read the damp faq you'll see the problem with tanking talked about somewhere in there. In short its not likely to be a part of a solution.

NT

 

[NT]

When picking a surveyor its necessary to find out if they have expertise with the type of building theyre surveying. In many cases they dont.

NT

 

[Lime]

David, from what you decribe, the first thing I would consider would be to build a retaining wall for the garden level and create an air gap of at least 2 feet around the wall of the house with good surface water drainage away from the house.

Make sure you go at least 6 inches below internal floor level.

The above is more important than the tanking as at present.

Keep an eye on things and take it one step at the time if you have to.

I would do that too.

 

[SGray]

David
I have in front of me a surveyors report on our house in which we found green mould behind the skirting and which smells damp in three rooms. You asked about cost - he has estimated that to tank our sitting room which is about 20' by 12' it will cost £3,500 - £4,500. (NB there is already a damp proof course on the floor so the estimate includes hacking off 600mm of wall plaster, exposing the edge of damp proof membrane by hacking away the edge of the floor screed, installing Newton new lath tanking membrane with waterproof plug fixings and seal between damp proof membrane and tanking, make good plaster and installing new skirting.)
I have been trying to find people who have found tanking to be a successful solution to their problems and people who have found it caused more problems in the long term. So far I have found three people who have found that tanking has been a success in their homes.

PC
I do not really understand the long term damage that tanking may cause. surely there are some situations when it may be a good idea?

 

[Lime]

Tanking doesn't really solve the damp problem it just prevents it being annoying.
The water is still in the walls.
As the water mounts up it seeks other and every escape it can i.e. over and around the tanking edge or through flaws within it.
Also if you ever get a flood in a fully tanked room the water doesn't drain away....important if it is a cellar.

 

[Lime]

I have in front of me a surveyors report on our house in which we found green mould behind the skirting

That puzzles me.
How can you have GREEN mould BEHIND the skirting board?
To be green it must be getting some light.
Behind the skirting it is dark.
That seems odd to me. :?

 

[NT]

http://periodpropertyshop.co.uk/phpBB2/viewtopic.php?t=6777
search for the word equilibrium

Also 'cement' & 'damage' in many places on this forum.

NT

 

[PC]

To S GRAY,

There's nothing wrong with the method of tanking you've suggested, ie. using a drainage membrane.

Problems can arise when using systems applied direct to the wall (CEMENTS) to hold back moisture.

PC

 

[Nemesis]

Sounds a great deal of money though - maybe SGray could do some of the work, and save a bit of cash?

But yes - it's a non-destructive method of dealing with damp which is supposed to actually work!

 

[SGray]

Nemesis
it sounds like a lot of money to us as well. We think we will lower the ground levels, dig the soak away and get rid of the weed proof membranes and concrete around the house and hope. When we get to the kitchen however, it is difficult to believe that the walls will ever dry out enough behind kichen cupboards so we may have to take a deep breath and add it to the cost of refitting the kitchen.

Lime
perhaps the mould went green after we left the skirting in the garden a few days - or perhaps it really was very badly fitted!