Drilling through the top of a wall

[benzinho]

Hi there,

i'm installing some extractor fans in my house and need to drill two 100mm or so holes in the wall from my bathroom into the roof space of my extension. To make it so that the ducting will come out above the ceiling in the extention I need to drill through the top of the wall in the bathroom. I'm a little worried that there may be a lintel or something structural that won't take kindly to have two dirty great holes drilled through it. Is it common to have a concrete lintel at the top of a wall? How can I tell if it is safe to drill through? Any help would be greatly appreciated.

Cheers

 

[Deluks]

Are you extracting to the outside, or into the roof space?
Why 2 holes, and is this a downstairs bathroom?

A bit more info would be helpful, but in general lintels are only above openings, doorway and windows etc.

 

[benzinho]

Hi there, cheers for the reply.

The bathroom is on the ground floor, but has no external walls. I'm hoping to run 100mm ducting through the wall near the ceiling and into the roof space above the room next door which has a lower ceiling. The room next door is a single storey extension and has a pitched roof, into which I am going to fit some kind of vent. The reason i'm doing two holes is that i am going to run ducting from a cooker hood in the kitchen through the bathroom to the same vent on the roof. I figure it is better to have the point where the two runs of ducting meet nearer to the vent to prevent the extracted air from one room going into the other.

Basically I just want to know if there any structural complications arising from drilling holes near where the wall meets the ceiling. The reason i am asking is because I started drilling an exploratory 10mm hole and it seemed very heavy going, which made me think it may be solid concrete. I tried drilling a bit lower down (too low to end up above the ceiling on the other side) and I seemed to get into cinder block fairly easily. It may be that there isn't any concrete nearer the top, and it could just be the position and the fact I couldn't get as much purchase on the drill, but i stopped drilling before I got too deep just so that I could double check i wasn't doing something really silly.

Hope that gives you a better idea.

Cheers
Ben

 

[noseall]

if there is a roof directly above a room then, depending on how the roof is pitched, there is a chance a timber wall plate will be situated just below ceiling line. this would make for stubborn drilling, particularly if you were using a masonry bit.

also be careful of long vent duct runs. you could end up with condensation forming inside the duct, and the fan may struggle.

 

[gangman]

Ducts have to be vented separately and as noseall said watch the long runs. I try to stick with 3m max.