Lintel bearing

[Feltwell]

Another question for you good people.....

My bathroom change involves making a hole in an internal brick wall, which is 6.5" thick (including plaster). Although the top of the section I want to remove is the top of the wall, I think it supports the joists of the attic floor above - before any work begins I'll investigate further - but it's a fair bet that a structural lintel will be required.

Usually that's an easy enough job, as generally you're making an opening in the middle of a wall, so having the recommended 6" of bearing either side for the lintel is easy enough. But in this case, on one side the removed section of wall will ideally be taken out flush with the inside of the exterior wall of the house. That exterior wall is a 9" solid brick wall.

Has anyone seen this done elsewhere, and what did they do? Create a hole in the external wall and only have 3" between the end of the lintel and the outside? I was wondering if fitting a small concrete lintel into the external wall, acting as a padstone below my new main lintel to spread the load into the external wall, would enable me to get away with a bearing of less than 6". I guess the other alternative is get a structural engineer to produce the calcs required for building regs, and have a steel lintel made up welded with a piece across the end - so a T-Shape when viewed from above - to get plenty of bearing onto that exterior wall.

 

[livias]

My immediate thought was 'joist hanger'. As there are zillions of different ones, that s not a complete solution

 

[CliffordPope]

Brick archway?

 

[stuart45]

How wide is the hole going to be?

 

[Me!]

fitting a small concrete lintel into the external wall, acting as a padstone below my new main lintel to spread the load into the external wall, would enable me to get away with a bearing of less than 6"

I have seen exactly this done before. A short lintel of about 18" or 2' set in to just the inner skin of an external 9" solid brick wall to provide a 4.5" load bearing point for another lintel at 90 degrees on top of the first. This was an existing construction in a house I was working on,and it appeared to have been like that for many years without any problems. I have no idea what modern regulations would say about it, but it certainly seemed to work fine.

 

[Feltwell]

How wide is the hole going to be?

5'. Ideally I'd want a catnic box lintel, as it's going to be a right pain lifting anything too heavy into this position.

 

[Westholme]

My house is full of lintels on 4½" bearings. Could you make the opening half a brick in from the external wall? What are your attic joists supporting above the opening? Air? A photo of a hand-drawn sketch might be useful.

 

[Feltwell]

Sounds like it will be case of getting a chat with the Building Control Officer. If I get the same one as last time then he's a funny chap - stickler for the rules one minute, then strangely pragmatic and uses common sense the next! Good to hear that others have seen examples of my thought of a small lintel acting as a padstone, with the main lintel bearing 4.5" onto it.

Leaving anything of the internal wall is not a great option - a bath will sit against that wall so to do that either the bath would have to be spaced away, or - more likely - the wall boxed in to make it flat again. A free standing bath isn't an option, it's a family bathroom with a shower over the bath - needs to have as few places for water to inadvertently go as possible! Bath must be sealed to the wall.

The lintel would need to support the floor joists of the attic room above, and apart from the floorboards and a small stud wall that's about it for fixed loads - other than that it's just our furniture and us moving about up there. So it won't need to be the world's beefiest lintel.

 

[Flyfisher]

I have no idea what modern regulations would say about it, but it certainly seemed to work fine.

That's a very good summary of so many things in our house and, I suspect, in many other old properties!

 

[stuart45]

4 inch bearing was quite common on many older houses, so I can't really see an issue with this.

 

[MikeG]

I'm not commenting on the specifics of the case (I'm an architect, not an engineer), but the 150mm bearing thing only applies to lintels over a certain length, and shorter ones are fine on 100mm. You'll need to check the manufacturer's blurb. You should also check that the build up above the lintel falls within the manufacturer's specification, because some lintels require a certain amount of masonry above them to make them work.