Concrete lintel under uneven joists

[qihto]

Hi, I'm replacing a crumbling brick arch with a concrete lintel. This lintel is above the end of a hallway and will support three first floor joists. One of the joists is significantly lower than the others and cannot be raised in line with the others.

One end of the lintel will be bedded into the exterior stone wall, and the other will be supported by an internal brick wall. I want to get the lintel as high as possible but for the lintel to be level there will be gaps between the lintel and the joists, what should I use to fill these gaps?

The bottom of the lintel will be about 4cm above the closest bricks, am I ok to fill this gap with a thick layer of mortar or should I source some thin bricks or other material?

 

[cdbe]

Slate, old tiles or something masonry would be best best below lintel aim for max 10mm mortar bed.

You could notch the bottom of the low joist a bit (say up to 25% of its depth) if that helps you.

 

[qihto]

Thanks, can I cut bricks in half length ways to create shorter bricks for this? Otherwise I'll get hold of some slate

 

[cdbe]

Yes.

 

[noseall]

Hi, I'm replacing a crumbling brick arch with a concrete lintel. This lintel is above the end of a hallway and will support three first floor joists. One of the joists is significantly lower than the others and cannot be raised in line with the others.

One end of the lintel will be bedded into the exterior stone wall, and the other will be supported by an internal brick wall. I want to get the lintel as high as possible but for the lintel to be level there will be gaps between the lintel and the joists, what should I use to fill these gaps?

The bottom of the lintel will be about 4cm above the closest bricks, am I ok to fill this gap with a thick layer of mortar or should I source some thin bricks or other material?

Single course concrete lintels work in composite with the masonry, i.e. they require a body of brickwork/blockwork above to function effectively. They should not bear any structural elements/point loads directly. You may need to set it lower so that you can build above it or replace it with a box Catnic or a deeper concrete lintel.

 

[stuart45]

As noseall's pointed out, you need to get a non composite lintel if you want concrete.

 

[qihto]

The lintel I've got is a 100x65 expamet pre-stressed concrete lintel, with a wooden wall plate between it and the joists

 

[stuart45]

A composite lintel like yours is designed to have 3 courses of brickwork or 1 course of blocks before any point loads are on top. Having the plate will help spread the load and it might work, but technically it's the wrong lintel.

 

[qihto]

Ok thank you, so this would be the correct lintel?

Catnic Internal Wall Box Lintel Standard Duty 1500 x 143 x 100mm Black

Catnic Internal Wall Box Lintel Standard Duty 1500 x 143 x 100mm Black

www.jewson.co.uk

 

[stuart45]

That lintel is designed to take point loads. If you've ever got any doubts about a catnic lintel where an excessively heavy point load is going into a lintel ring catnic and they can advise whether a heavy duty or extra heavy duty is needed.
In your case the one in your link should be fine.

 

[qihto]

Perfect, thanks for your help