Is it safe to drill under a lintel?

[henry1]

I'm thinking of putting a boiler near the window. The flue will most likely end up going under the lintel. Being the flue, the hole is not going to be small. It doesn't sound safe to me to be drilling such a big hole under the window lintel. What do you guys think?

 

[PrenticeBoyofDerry]

Should not be drilling holes directly under supporting lintels, nor should flues be within 300mm horizontal of openable window/door

 

[henry1]

The flue will be close to 300mm away from the window, might need a plume kit. However, I think it still is going to fall under the lintel, so I might not be able to proceed.
I'll remove the plaster tonight to confirm where the lintel ends.
Thanks for confirming.

 

[PrenticeBoyofDerry]

Ideally you need 150mm bearing for a supporting lintel at each opening. Coring a flue hole directly beneath that bearing is very likely compromise the structure of it.
Then there other structural consideration to make if the lintel bearing is greater than 150mm, as it maybe that it is required to support the lintel and load.

 

[henry1]

It's a very wide window, so I wouldn't be surprised if the lintel bearing is much more than 150mm. In any case, I won't be drilling underneath. Will remove plaster first to see where the lintel ends and if there is space next to it for a flue.
I'm glad I didn't listen blindly to the gas engineer...

 

[Blagard]

Sound like you will end up with a hole in a suitable place but don't forget all the other constraints.
See https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/468872/ADJ_LOCKED.pdf page 49