Damp & Rat trap bonding

parkertl

Please be gentle with me, this is my first posting :eek: , although I have been browsing the site for a while now.
We are in the process of buying a new (old) house.
The survey has come back reporting moderate damp in some rooms.
We are aware that the house has been constructed using rat trap bonding!!?!!
Can anyone tell me the best way to deal with the damp?
Thanks

weekendwarrior

I don't think the fact that your house has been constructed using rat trap bonding will have any effect on what type of damp proof course you have installed, but personally I always have these installed - electro osmosis DPC as they are much cleaner and easier to install then chemical ones.

iamcornholio

The brick bond (rat trap) is irrelevent to the existance of dampness.

Your survey should qualify what type of dampness it is (rising, penetrating, condensation etc) and give a likely cause (no Damp Proof Course, leaking gutters, no ventilation etc).

Be careful as to what type of survey you have had. Some are very limited and infer dampness, when none really exists.

I would also like more information as to the type of survey. Rat trap bond is/was not normally used on buildings, so has the surveyor got this right or is he just trying to impress and mislead?

parkertl

The homebuyers report says:
The damp proof course is concealed within the main walls, although in a building of this age, it is likely to be of slate....it will have broken down and become ineffective....
Tests with a moisture meter were undertaken to acessible internal faces of the main walls within the groundfloor accomodation. Moderate to high readings were recorded in a number of locations.
No significant condensation was found.

It was the neighbours that told me about the rat trap bonding.

parkertl

Hi, We have know had a specialist company take a look.
They are recommending that the put in a chemical damp course by drilling holes externally into the render and internally into the plaster.
They have quoted approx £600 for that.
Then there is making good the outside and replastering the inside, which needs doing anyway.
They have said that they cannot provide a guarentee for the damp course because of the rat trap bonding, but would be able to guarentee the internal plaster.
Does anyone have any advice?

weekendwarrior

parkertl wrote: »

Hi, We have know had a specialist company take a look.
They are recommending that the put in a chemical damp course by drilling holes externally into the render and internally into the plaster.
They have quoted approx £600 for that.
Then there is making good the outside and replastering the inside, which needs doing anyway.
They have said that they cannot provide a guarentee for the damp course because of the rat trap bonding, but would be able to guarentee the internal plaster.
Does anyone have any advice?

Get a few more quotes and opinions.

Why anyone would use rat trap bonding for foundations is beyond me as it is considered weak.

I don't like the sound of it to be honest and I'd check the plaster internally, when you nock it with your knuckles does it sound hollow?

The outside render might need replacing, perhaps the damp could be penetrating and not rising?

I'd definately get a few more damp experts around and ask their opinions!