weatherproof flint walls

[sewingsandi2001]

Help! We are renovating a 300 year old norfolk flint cottage. We are having problems with severe rain driving in above our new bathroom windows (downstairs). It was damp before, but we thought it was to do with the old windows and thick artex from the 70's. It seems to be the whole side of the house. I have tried Thompsons sealer, but it has not worked. The pointing looks in good repair, so I thought it must be pourous. So what should we do? Don't want to have a re-point if not necessary. Sandi

[Roger]

The message from [e-mail] contains these words:

Well flint is not porous so if it isn't getting in through the pointing it must be getting in somewhere else. The obvious place is via a leak in the roof. Once in the wall water can take a circuitous route downwards looking for a way out.

I have an old Yorkshire hovel with 2 foot thick rubble filled stone walls. Twice in the last 30 years I have found a continuous thin stream of water running out of the wall from above a window during heavy rain but in neither case has there been a recurrence and I have yet to trace the source of either leak. If it happened every time it rained I might have a better chance of tracking the leaks down and more incentive as well.

I believe flint walls generally have a mortared core rather than loose rubble but such cores are likely to contain sufficient voids to provide a pathway for water, particularly after 300 years, and could make the actual leak even more remote from the resurgence than would otherwise be the case.

[The Natural Philosopher]

That would be my suspicion too.

in my case in a timber farme it was the barge boards on the gable ends ..rain was blowing right through what was left of them into the wall cavity, and it ended up oozing out of the window surrunds.

Check barge and soffit areas.

Also if any drip boards are installed, but have rotted.

>

[meow2222]

You really need to ask people with expertise on this, this is not a pp oriented forum.

[The Natural Philosopher]

oh here we go again.

A flint wall is essentially a slightly more pourous form of concrete, being made up of the same three materials..sand, cement and flint.

Thats as old as the hills and as modern as you like.

Not much has changed apart from portland cement replacing lime, since Roman times.

Flint walls do not let water in. Not unless there are visible holes in the wall.

so its getting in either through a visible hole, or far more likley, a less visible one somewhere behind the outer layer.