Fan Hole requirements

[martysparky]

On a job at mo and fitting a cooker hood with external ventilation.

The hole when drilled seems a little close to the joists. The top of the hole will be about 150mm from ceiling and about 100mm from a vertical drop.

could anyone clarify this situation?

Cheers.

 

[acat]

IMO main over riding factor is cooker hood should be 650mm to 750mm above hob surface or inline with manufacturers instructions any lower we have a fire hazard.

Considering the width of most fans I dont see that being 150mm away from joist will be a problem as rest of the wall should support joist even if just a hole was left but after fan is installed that would give more support.

The cause for concern for me is the 100mm away from a vertical drop that could be the weak point and may need more support unless its a corner wall then it should be ok.

May be wrong but thats how I would look at it.

Chris

 

[martysparky]

IMO main over riding factor is cooker hood should be 650mm to 750mm above hob surface or inline with manufacturers instructions any lower we have a fire hazard.

Considering the width of most fans I dont see that being 150mm away from joist will be a problem as rest of the wall should support joist even if just a hole was left but after fan is installed that would give more support.

The cause for concern for me is the 100mm away from a vertical drop that could be the weak point and may need more support unless its a corner wall then it should be ok.

May be wrong but thats how I would look at it.

Chris

The hood is fitted at the correct height, that ok.

Thanks for the comment on the joist I was thinking the same and clarifies my thought.

What I mean about a vertical drop is the cooker cable.

 

[ian.settle1]

On a job at mo and fitting a cooker hood with external ventilation.

The hole when drilled seems a little close to the joists. The top of the hole will be about 150mm from ceiling and about 100mm from a vertical drop.

could anyone clarify this situation?

Cheers.

What joists are you talking about that it is close to?

Is the Hole below or above ceiling?

100mm from what vertical drop?

 

[martysparky]

What joists are you talking about that it is close to?

Is the Hole below or above ceiling?

100mm from what vertical drop?

150mm below ceiling

100mm from cooker cable vertical drop

 

[ian.settle1]

150mm below ceiling

100mm from cooker cable vertical drop

What has the joists got to do with it????

If cable is buried in wall no problem

 

[Des 56]

Its never going to affect a joist
What ducting did you use?

 

[martysparky]

Its never going to affect a joist
What ducting did you use?

Going to use a spring bend connected to a rigid PVC through cavity.

What has the joists got to do with it????

If cable is buried in wall no problem

I would usually go through the wall about 200mm down from ceiling joists so was a little concerned about integrity of the weight load from a joist and removing support with a hole.

e.g. If the top of the hole was touching the joist the joist would fall out because of no support so was wondering how close you can make a hole to the joist without affecting the structure.

The cable is buried, good, Thanks

 

[Deleted member 9648]

Going to use a spring bend connected to a rigid PVC through cavity.




I would usually go through the wall about 200mm down from ceiling joists so was a little concerned about integrity of the weight load from a joist and removing support with a hole.

e.g. If the top of the hole was touching the joist the joist would fall out because of no support so was wondering how close you can make a hole to the joist without affecting the structure.

Thats a very good point....and one I dont know the answer to.(but would like to for future reference)

 

[gaffer]

The lintel above my kitchen window is 150mm deep and there are six joists on top of it .So I would say you should be ok,depends on the materials the wall is constructed from.Also with the hole being circular you effectively created an arch supporting anything above.What we really need is the input of a structural engineer.Hope this helps.

 

[martysparky]

Nice one guys

Drilled it today and all is well. Just hope and pray it stays that way.

To be honest with the regs saying the hood has to be 650 - 750 above the cooker it does not give a great deal of room to play with, I do however try and get the hole between joists but obviously not always and easy option to tell the customer to re model their newly fitted kitchen according to the fan hole.

Any more info on this would be greatly appreciated.

I have to totally agree on the structural engineer comment by gaffer. Would be a good input to us all I'm sure.

Thats a very good point....and one I dont know the answer to.(but would like to for future reference)

Hey, if you do find the answer before I do please post it..