Opening up a chimney breast

[ferdinand2000]

I think this one best fits in the building forum, and I'd be grateful for any advice. Apologies for the long post, but I've tried to be clear.

I'm turning an ex-living room into a kitchen in a 1915 house, and opening up the chimney breast to put the cooker there. When I open it up the hole will be 1m wide and 1.7-1.8m high (or the height I need to cook comfortably with the hood being low enough so that smaller people can still reach the controls). The fireplace will be about 0.35m deep.

I will be using a built-in cooker hood in the old chimney, extracted up then straight backwards through the narrow cavity wall.

It's the first one I've done myself, so I'd welcome a common sense check. My questions, and what I *think* are the answers are these. I'd be grateful for any corrections.

- What height above ground does the outlet from the extraction need to be on the outside? Are there any regs on that? Mine seems to be headed for 2.25m-ish over a side path to the back garden.

The chimney is properly capped, but has not been properly ventilated, and there is some efflorescence on the outside up to about 5 courses. I'm thinking that this is probably down to decades of the previous late 60s gas heater, which simply had an outlet into the capped chimney via a 'postbox' in a light metal plate, and an unventilated chimney for the 3 years the house has been empty. There was no build up of debris in the fireplace, and no general damp problems.
- Will I be fairly safe to expect that efflorescence to clear up over time, and not worry for now?

I will be putting in a 1.2m lintel. Given that I will be opening a 3" high hole (one row of bricks) for a steel lintel 28mm high what do I wedge the ends up with? Can I use 2" stacks of hammered in slate?

I'll check whether the chimney needs sweeping if they missed that last time.

The actual cooker install, wiring etc will be done by tradesmen.

Is there anything else I need to be careful about?

Thanks

Ferdinand

 

[dann09]

If you are still with us:


1. The hood has to be the regulation ht. above the hob - 760mm.
It would be dangerous for children to reach up - why not drop the controlling spur ie. the neoned, switched FCU, to a convenient position. Leave the hood controls set at whatever, and use the FCU to switch ON and OFF?

2. Research on here the recent posts ref just this subject.
At the earliest opportunty, smoke test and sweep the flue - a must.
Ht. of ext. terminal is fine - is this over a private pathway?

3. Efflorescence could be from historical gas fumes cooling, or possibly the flaunching and brickwork of the stack is degrading - an inspection req'd. The in-situ terminal might have to be lifted to provide a view inside the flue.

4. Be more specific ref the lintel, typically, slate is used to wedge, but more detail is req'd. A SE is not req'd. FWIW, BCO should be informed of your proposal.

5. As mentioned elsewhere, before doing any work make up a homemade plan and sections drawing with dimensions, show locations of all apps and accessories, and FFL's.