I will be fitting a cooker hood (not done one before). I guess it will
be one with a squarish brushed metal riser. Some questions:

1. Is the fan usually integrated into the hood, or is it above the
hood in the riser, or in the ceiling ?

2. The first stage will be to fit the ducting into the ceiling so the
ceiling can be plastered up etc. There will basically be a stub of
pipe sticking downwards out of the ceiling. When you later come to fit
the hood and riser, how much tolerance do you get left or right to
position it ? For example, assuming a flexible pipe is used for part
of the connection, you could move the duct left or right by about
inside riser width - outside duct width / 2.

Cheers,
Simon.

sm_jamieson wrote:
I will be fitting a cooker hood (not done one before). I guess it will
be one with a squarish brushed metal riser. Some questions:

1. Is the fan usually integrated into the hood, or is it above the
hood in the riser, or in the ceiling ?

In the ones I've fitted its in the hood.

2. The first stage will be to fit the ducting into the ceiling so the
ceiling can be plastered up etc. There will basically be a stub of
pipe sticking downwards out of the ceiling. When you later come to fit
the hood and riser, how much tolerance do you get left or right to
position it ? For example, assuming a flexible pipe is used for part
of the connection, you could move the duct left or right by about
inside riser width - outside duct width / 2.

Usually connected by a flexible connector, the sheet metal riser is just a
cover. An inch each way should be about right.


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk

Usually connected by a flexible connector, the sheet metal riser is just a
cover. An inch each way should be about right.

Is it not usual to have an elbow straight out through the wall, rather than
going up into the ceiling void?
The reason I ask is that I intend to fit a cooker hood, but there is a joist
running parallel to the wall in the ceiling directly above the hob location.
Probably occupies a 3" strip of space from the wall IYSWIM.

Phil

sm_jamieson wrote:
I will be fitting a cooker hood (not done one before). I guess it will
be one with a squarish brushed metal riser. Some questions:

1. Is the fan usually integrated into the hood, or is it above the
hood in the riser, or in the ceiling ?

It will be in the hood. The metal riser is just to look nice and cover the
ducting.

2. The first stage will be to fit the ducting into the ceiling so the
ceiling can be plastered up etc. There will basically be a stub of
pipe sticking downwards out of the ceiling. When you later come to fit
the hood and riser, how much tolerance do you get left or right to
position it ? For example, assuming a flexible pipe is used for part
of the connection, you could move the duct left or right by about
inside riser width - outside duct width / 2.

Extractor hoods should use 5 inch ducting so you do have a few inches either
side to move your pipe.
--
Adam

On 2 Aug, 19:46, sm_jamieson wrote:
I will be fitting a cooker hood (not done one before). I guess it will
be one with a squarish brushed metal riser. Some questions:

1. Is the fan usually integrated into the hood, or is it above the
hood in the riser, or in the ceiling ?

all depends on the design! our current is a Stoves which teh hood part
is abt 30mm thick the works are in the lower part of the riser.

Others, especially with triangular hoods the gubbins will usually be
within the triangle as you look

If you have the resources (incl. time), consider "remotely sited fans"
that lead back to just the grease filters above your hob etc - mucho
quiet even on high speeds. De dietrich (and others I am sure) did some
when I last looked into this 10yrs ago - gasp!!

Some ordinary yet expensive "designer" hoods I've seen n heard at
friends houses are not used even on the lowest settings cos of the
racket/vibration/embarassment caused (unless absolutely necessary....)

Cheers
Jim K

In message HJ_5o.20159$VW2.12704@hurricane, ARWadsworth
writes
sm_jamieson wrote:
I will be fitting a cooker hood (not done one before). I guess it will
be one with a squarish brushed metal riser. Some questions:

1. Is the fan usually integrated into the hood, or is it above the
hood in the riser, or in the ceiling ?

It will be in the hood. The metal riser is just to look nice and cover the
ducting.

2. The first stage will be to fit the ducting into the ceiling so the
ceiling can be plastered up etc. There will basically be a stub of
pipe sticking downwards out of the ceiling. When you later come to fit
the hood and riser, how much tolerance do you get left or right to
position it ? For example, assuming a flexible pipe is used for part
of the connection, you could move the duct left or right by about
inside riser width - outside duct width / 2.

Extractor hoods should use 5 inch ducting so you do have a few inches either
side to move your pipe.

I briefly considered ducting the output from the cooker hood on my
wife's flat (rented out now). The fan is mounted in the hood and outputs
vertically through a stub of duct, probably 5" x 5" as you mention.
Plenty of space along the top of the kitchen units but a concrete lintel
prohibiting access through the cavity wall.

4" duct and drop down the wall in rectangular section to an existing
vent was do-able but never happened. Oh well! See how the mould goes
this winter:-(

One obstacle was adapting the 5x5 to 4" round.

regards

--
Tim Lamb

On 3 Aug, 21:21, Jim K wrote:
On 2 Aug, 19:46, sm_jamieson wrote:

I will be fitting a cooker hood (not done one before). I guess it will
be one with a squarish brushed metal riser. Some questions:

1. Is the fan usually integrated into the hood, or is it above the
hood in the riser, or in the ceiling ?

all depends on the design! our current is a Stoves which teh hood part
is abt 30mm thick the works are in the lower part of the riser.

Others, especially with triangular hoods the gubbins will usually be
within the triangle as you look

If you have the resources (incl. time), consider "remotely sited fans"
that lead back to just the grease filters above your hob etc - mucho
quiet even on high speeds. De dietrich (and others I am sure) did some
when I last looked into this *10yrs ago - gasp!!

Thats what I really wanted, since I had an idea to include some kind
of flap such that at single fan could either drive the cooker hood or
an extractor grill in the ceiling. So it could be used to pull out hot
air gathered by the ceiling in summer (inside ceiling slopes up from 8
foot to 10 foot).
Access to the fan for maintenance might be interesting though. The fan
would be in a small loft area in a single storey extension ceiling !
Simon.

On 4 Aug, 08:50, sm_jamieson wrote:

Access to the fan for maintenance might be interesting though. The fan
would be in a small loft area in a single storey extension ceiling !
Simon.

could you maybe mount the fan(s) outside?

stick a velux or two in the roof - left open on "vent" in summer?
stand on a chair you can reach 10ft......

Cheers
Jim K