Bringing 4" vent through beam

J

jrewing

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I am looking at installing an island extractor hood in my kitchen. Getting an electric supply to the unit is no problem, but getting the vent to an outside wall means going through a wooden beam.

Any suggestions for bringing a 4" vent through a 9" x 2" beam ? Should I use a short section of a smaller diameter vent and put a 2" (for example) hole through the beam and connect to 4" each end ?

Or is there anyway to brace the beam top and bottom, so I can put the full 4" hole through ?

I would prefer to stick to 4" all the way to maximize the extraction efficiency.

I can't imagine there is much load on the beam in any case, as there is little furniture in the bedroom above.

All suggestions welcome - thanks !
JR
 
I'm no expert, but tampering with beams seems dodgy to me. I wouldn't think the lack of furniture upstairs is significant - Is the beam holding the room up, rather than the contents of the room? Can you pipe out the vent just below the beam?
 
Not sure if it's similar but seem a documentary on holmes on homes last week where it cost 8K to repair a house because the contractor cut through a beam to route a vent for heating...as a result structural damage was caused because it was a load bearing beam....
 
As rainyday has said it is not advisable to cut through a beam. Yo umight get away with notching a beam but not removing up to 50% of it. the beam is there for a reason and supporting furniture would not be the main one. Can you cut through under the beam and maybe hide the extract in one of the storage units?
 
I assume the "beam" you refer to is a standard floor joist, 9x2". Anyway it would not be possible to make a 2" slot through a joist as suggested. There are a number of "rules of thumb" regarding notching and drilling of floor joists, they can be found in the Homebond builders' manual. Generally holes must not be more than 1/8th of the depth of the joist, and the bust be bored on the central axis and their distance from the end bearing is restricted. I think you'll really need to look at solving your extraction problem by finding another route. Can the ducting be boxed out or be routed in overhead cabinets?
 
Thanks all for the advice, looks like we will have to run it on the underside of the ceiling and box it out.
Luckily it's only about one metre, so it won't provide too much of an eyesore.

Thanks, JR
 
Try and design/ build the boxing out so as to make it appear like it's intentional/ was always there/ isn't just hiding something. Depending on the style of your kitchen (minimalist, contemporary or country pine?) you can use plant on mouldings or trim to improve the appearance of the boxing out. You may decide to make a feature of it (with shelf for knick knacks) or leave plain and paint it to blend in with wall or ceiling.
 
Does anyone know if this is a big job to put a vent for an island hood through bison slabs?
 
If by Bison slab you mean pre cast conc slab , nah not really that big of a job , simple matter of getting a guy with a core drill , just be careful he dose'nt core thru one of the pre-stressed tendons , if there is any.
 
To Jrewing: Would it be possible to run the duct paralel with the ceiling beams hidden within the ceiling? Instead of cutting through the beams? Though the outside wall at which it ends would be a different one.
 
Heinbloed,
no, unfortunately it's at a position where I hit joists whichever direction I go. I'll be going for the box-out option.
 
I have also seen this done in exposed steel spiroduct, which is then painted to match wall colour, can look good in a contemporary set up.
 
The duct does not have to be 4" circular duct. You can get a rectangular duct with circular adapters at each end which should make it a bit neater.
 
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