We get damp patches around the base of our fire breast walls , it dries out on warm days but with just a heavy shower the damp patches darker with moisture and a smell comes with it . The fire place is now empty and has been for about six years .
It started as a coal fire then a gas but now we have a combi boiler .
The chimney is capped and the room is well ventillated

Greg lorimer, August 2009

Amazon sell this book...

Everything You Need to Know About Maintaining Your Home by Jeff Howell for £6.21 and it's excellent.

Given that your Chim Breast gets damp at the bottom particularly after heavy rain I would guess it's rain related and that the water is not coming from above but from below.

I suspect you probably have suspended timber floors and that the water table where you live is high. You may have insuficient (or even blocked) ventilation under the floor which will not help the natural damp in the soil to dry out.

Next time you have heavy rain, pull back the carpet and lift a floor board - use a torch and maybe a mirror to take a peek down below. If you see moisture then check and or improve the ventilation.

The smell may be because of the lack of ventilation - I hope it's not connected with defective drains.

Good luck...

Peccavi, August 2009