Fitting cooker hood in chimney breast

[LordKitchener]

Hi,

Me and the missus intend to fit a Bosch DHU625MGB cooker hood into the 1920s chimney breast shown in the photo below.

We will only use the hood in recirculation mode.

The gas oven will be the one in the picture.

Since the photo was taken, the floor has been tiled, but there will be a more than legal clearance distance of 710mm between the top of the oven and the bottom of the cooker hood, once it is fitted.

The cooker hood will be fitted flush with the bottom of the lintel, below some form of plasterboard across the opening of the chimney breast.

Questions:-

1. How should we cover the opening in the chimney breast, to ensure it is fire safe, easily wipeable, etc.?

a) Fireboard?
b) Ordinary plaster board?


2. What materials / coverings could we use on top of the fireboard / plasterboard, should we wish to?


3. How do we best tackle the soot which falls down the chimney breast? It falls on to a piece of cardboard at the moment and creates a hell of a racket. I expect it would be similar if it fell on plasterboard.

The chimney breast was swept fairly recently.

One obvious problem is that there is no chimney cowl.

Would putting loft insulation material on top of the plasterboard be a safe and effective option to deaden the sound of the falling soot?


4. Although we are not using the old chimney breast as a flue, would it be a good idea to vent it in some way?

If so, where and how?

So, all in all, not a lot of questions for a first-time poster.


Best,

Lord Kitchener

Kitchen chimney breast

• LordKitchener
• 3 Aug 2011
• 1

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[PrenticeBoyofDerry]

Sweep Chimney then soot should not be a real issue
Normal Plasterboard will be fine.
Install rain stop cowl and vent the chimney.

 

[Richard C]

Is this a new kitchen as opposed to a renovation? if so, Building Regulations require you install forced ventilation. An extractor hood won’t work when installed at the bottom of a chimney flue; the fans are not capable of shifting such a huge vertical column of air. Recirculation hoods are crap anyway, your kitchen will permanently stink of food, you’ll have congealed grease everywhere & you’ll get problems with condensation.

Unused chimney flues should always be vented at the bottom & have a rain cap fitted at the top or you’ll eventually get condensation/damp problems.

 

[rarara]

An extractor hood won’t work when installed at the bottom of a chimney flue; the fans are not capable of shifting such a huge vertical column of air.

Is this factual? Am wondering since I am in the process of venting a hood up a chimney. The opening already provides a fair 'sook' upwards so surely a cooker hood fan at the bottom will fairly get anything sent its way shifting?? The vertical column gets drawn up by the air passing over the top of the chimney, so in reality shouldn't need pushed - no?

 

[JohnD]

Recirculation hoods are crap anyway, your kitchen will permanently stink of food, you’ll have congealed grease everywhere & you’ll get problems with condensation.

100% agree.

But warm air does tend to travel up a chimney anyway, even without a fan. You will need a liner though, to prevent grease and condensation coating the flue and soaking into the brickwork.

 

[Richard C]

Many cheap extractors have a maximum horizontal duct length (some as low as 3 meters) let alone trying to shift a 6m vertical column of air up what could be an old 300mm or more diameter flue. Its true there should be a natural updraft but if you’ve ever had an open fire or stove you will experience occasions where flue draught is virtually non existent & you end up smoked out until the fire gets going sufficiently to generate enough hot air to create an updraught.

I don’t know if the work your doing requires inspection but I’m sure I’ve seen a post on the Forum (some time ago) where a BI refused to accept a cooker hood feeding an old flue as the principle method of extraction required in a kitchen; they had to install an additional wall mounted extractor fan before the BI would pass it.

 

[foxhole]

OP said he is using in recirculation mode only so will discharge into kitchen?

 

[Richard C]

OP said he is using in recirculation mode only so will discharge into kitchen?

That was the OP LordKitchener; rarara who asked the question has hijacked his thread

Slapped wrist for you rarara