DPC in old properties....

[kevinr]

Hi,

I suspect this has been covered in great detail already, having a read through old posts, but thought i would be lazy and ask anyway!

I have had an offer agreed on a property believed to have been built in 1760. The property is built of brick and stone on a raft foundation. The house has no DPC and there is some evidence of water penetration (building survey is being carried out this week), one of the internal walls is bare and the face of the brick has been blown off by water, it looks as though this section of brick has been re-pointed with a cement based mortar, which may well be the cause of this problem by trapping the water in the brickwork. All in all the house is in amazing condition for its age, the outside has been rendered whilst the inside has been dry lined. There are no marks on the dry lining / render to suggest damp problems (tide marks etc). The original windows have been replaced with UPVC (at present its is not listed, though i will be getting it listed to stop it being torn down in the future) My question is whether a DPC injection is worthwhile, i am of the belief that the best course of action is to perhaps install ventilation at the base / top of the dry lining, to aid in air circulation, anything other than DPC injection!. The floors have been tiled throughout which may also be a problem forcing damp up through the walls?

All this is speculative at present as the building survey is yet to be completed, i have asked the surveyor to pay particular attention to damp levels and comment on possible solutions to minimise future problems.

Just wanted to ask the experts to get an experienced opinion.

ps - rainwater goods etc all look fine, no water marks on the outside.

Thanks very much!

 

[kevinr]

One of the original fireplaces has a modern multi-fuel stove within it, basically its been opened up much like an inglenook fireplace, the other fireplace has been covered up all together, the current vendor has advised that an old oil fired boiler was in this fireplace which has since been removed.

Is it worthwhile opening up this fireplace?

If i understand correctly an open fire should aid air circulation in the house? the installation of sealed DG probably won't help!

Thanks again

 

[Penners]

I'm a bit puzzled by the raft foundation for a 1760 house. Others may blow me out of the water, but I don't think this is likely.

Do you mean that there is concrete underneath the floor tiles? If so, I suspect that this has been poured as a floor well after the construction of the house - probably 20th century.

Considering your observations about the condition of the house, with no sign of damp on the dry linings, I think I would adopt that well-known American philosophy: "If it ain't broke, don't fix it". An injected dpc is far from a guarantee against damp, particularly in a stone wall, and I wouldn't want to risk wasting my money.

The walls may well be a bit damp behind the dry-lining (otherwise, why is there?), specially if concrete floors have been poured. As you suggest, this could be forcing damp outwards to the walls.

If it were my house, I think I would do as you say - ensure that there is a flow of air between the dry lining and the walls (always assuming that the dry lining is battened away from the walls to leave an air gap). I would also get rid of the cement pointing on the damp brick wall, and replace this with lime mortar.

Other than that, it doesn't sound as though you've got too much to worry about - unless of course your surveyor turns up any nasties.

You say that you'll be getting the house listed - it isn't quite as easy as that! Others will be able to explain how buildings get listed much better than I can, but it's not just a question of the owner expressing the wish...!

 

[kevinr]

Hi Penner,

Thanks for the info, the current vendor had a structural survey carried out, mainly because of cracking in the external render. The surveyor dug trenches at the four corners of the house to reveal the foundations, they dated the property based on their findings, a raft foundation of 250-450mm built with brick and stone,although they didn't mention the materials used for the foundation.

Of course they may well be wrong! This also seemed suspect to me as i have looked at a few houses of this sort of age, two of them didn't have foundations at all (one turned out to be mud n stud)

The cracking was down to movement but nothing unusual for this type of house as they stated it should move due to the construction.

I do know that the house was renovated at some point in the past, i suppose it is likely that the slab was poured when this was done, perhaps the surveyor didn't explain their method for dating properly?!

Thanks again, appreciate you taking the time to answer such novice questions!

 

[Moo]

i have asked the surveyor to pay particular attention to damp levels and comment on possible solutions to minimise future problems.

If you've been reading previous threads about damp you probably know what I'm going to say. But just in case - do make sure you get a surveyor who knows about old properties: if he brings out a dampmeter and even mentions free consultations with damp experts, send him packing and come back to the forum to find someone in your area who really knows his job.

 

[kevinr]

Sorry i didn't explain that properly, i had an architect view the house with me, as i want to extend it. The extension will be separate apart from a "link" at the ground floor, to protect the existing house and allow it to move.

The architect said that it is very likely that the original house will be spot listed once the work is complete, as he thinks the building control guys will as a matter of course contact a conservation officer.

I hope this is the case, would be a shame to see such a nice house torn down in the future.

Thanks

 

[kevinr]

Thanks Moo,

Yes the surveyor has experience with this type of house, he's been surveying for 28 years and at least claims that half his work involves period houses.

I was given his number on recommendation so fingers crossed he's the man for the job!

 

[NT]

The Damp FAQ thread should explain things. Worth putting in an injected dpc? No, not at all an effective solution.

A raft foundation sounds very unlikely to me too, but thats not a subject I know enough about to be sure. Perhaps the builders were very forward thinking...

Any good surveyor will use a damp meter for legal reasons, its how they interpret its readings that counts.


NT

 

[Lime]

If this 1760s house has a raft foundation the question that comes to my mind is why?

Raft foundations were used in the past but most consisted of wood or organic material to provide a solid base in mashy conditions hence the expression.

All in all the house is in amazing condition for its age

However the very first thing I thought of when I read that was that this house has been moved onto a more modern foundation.
(just a guess)

 

[Nemesis]

I certainly wouldn't bank on this being listed - it would have to be of national historic and architectural interest and it sounds as though it has been very altered.

The CO isn't the person who lists - the Secretary of State does, after advice from English Heritage.