Unused Chimney stack ventilation

[Mike A.]

I have a 1950's built house with two rather high chimney stacks, each with two chambers - one for the lounge and bedroom above, one for the dining room and bedroom above. The roof is steeply pitched and the chimneys are built out from the outside wall and are around 35 courses of bricks above gutter level - access is difficult.

Only the lounge chimney is occasionally used for an open fire. The fireplaces for the others are bricked up and have internal ventilation bricks.

Currently we are having the top 6 courses of each chimney being rebuilt. Scaffolding is up and work is in progress as I write.

Question: I'm wondering, late in the day, if we should add a chimney pot insert to each of the 3 unused stacks the prevent rain ingress. I'm looking at some from Redbank Manufacturing

- look under Chimney inserts.

We've been in this house 6 years and I'm not aware of any problems with the open pots. Clearly the insert would reduce rain ingress, but I just wonder if the more restricted ventilation of the insert might negate any benefit this offers?

I'm totally ignorant in this area so any direction or pearls of wisdom would be appreciated.

Mike A.

[fred]

In article , Mike A. writes

A cap is definitely a good idea for the unused flues, as well as the ones you point out you can just add a separate aftermarket cap:

'll not need much of a draught to keep it dry and leaving it fully open will result in a lot of warm air being lost through the vent.

IMO an internal room vent (as you have) is best as warm air from the room rises up through the chimney by convection keeping it dry but others here have successfully vented the base of the chimney to the outside and claim there is sufficient airflow to keep it dry.

[Mike A.]

Fred, Thanks for the info - very useful.

Mike A.