Fireplaces and damp

[Zoro123]

We bought an old house 1907 and all the chimneys have been closed up. The house is damp and we’ve been told it may be a ventilation issue, I wonder if opening fireplaces will help this? We want to open them anyway but wondered if that would be another reason to? Has anyone any wisdom in opening fireplaces and any dos or dont’s?

All flues need to be ventilated top and bottom. An airbrick-sized hole will do. You can put it at the side of the chimneybreast to be less conspicuous.

Each chimney may have two or more flues in it (usually one in each level of the house)

Unventilated flues get internal condensation.

You may also get damp near the top, if rain is getting in. This tends to leave yellow or brown stains on the plaster from the soot and tar in old chimneys.

Or you may get damp at the bottom. This may be due to the absence of a DPC under the hearth, often aggravated by heaps of builders rubble thrown into the fireplace before it was bricked up. This is best dealt with by opening up and digging out the hearth so that air currents can dry out the brickwork. Damp can only rise a few courses in clean, bare, ventilated brick. Chemical injections are useless.

In an old house, trouble may be avoided by demolishing the chimneys down into the loft, and tiling the roof to cover the hole. This means you no longer have to repair pointing, flashing and flaunching. These are expensive when you need somebody to clamber up scaffolding and work at height.