How to set a steel lintel over a door frame

[jim]

Detached garage: I'm replacing the timber frame (925mm wide overall) for the side entry door. The wall is single brick with buttresses. The brick (soldier) course over the frame lacks a lintel, so wish to add a steel L section.

Can someone kindly help me step by step with how to set the lintel and where to put mortar.

First, how should the ends of the lintel be placed on the supporting bricks? On a thin bed of mortar? - if so how thick?

Next SFAIUI a PVC dpc should be placed on the lintel. Is this laid on the steel lintel directly without a mortar bed? And does it go up and over the rear upright of the L?

Next the layer of mortar for the new soldier course: - is this continued up the rear L upright?

The lintel I purchased has a lip at the top of the rear upright which sticks out 15mm at 45deg. What is this for and how is it left when finished?

How should the dpc be left so that it looks trim? Should any of it be visible?

Nothing else I need to watch out for?

TIA for all help.

[Roger Mills]

Are you sure you *need* a lintel? What's above it, in terms of brick courses etc.? Does that part of the wall support the roof? If there's not much to hold up, a row of soldiers may well be more than sufficient.

Assuming you *do* need a lintel, I would simply use a piece of 6mm thick

100mm angle, about 250mm longer than the doorway width. It sounds as if the lintel you have was intended for a cavity wall, and includes a cavity tray - which you neither need nor want. I've never heard of putting a DPC between a lintel and the wall above - what's it supposed to *do*?

I don't know whether this is the official method, but this is what I would do if fitting a lintel in your circumstances:

• Rake out the mortar either side of the door, from the course level with the top of the doorway, sufficient to be able to slide the lintel in from inside the garage, with a few mm of clearance between the lintel and the soldiers

• Apply a thin layer of mortar to the upper horizontal surface of the lintel, and slide it in

• Use Acrows to jack it up so that it 'beds' under the soldiers, and any surplus mortar squeezes out

• Use thin slate (not mortar) to pack between the underside of the ends of the lintel and the supporting brickwork

• Re-point the mortar joints which you have disturbed

[dave]

[...]

That's pretty interesting. Any chance the OP, you can post some pics step-by-step? That's be a good ref for any other's doing it! (Like me

- maybe perhaps possibly :-) )

[jim]

Reason for this is a rotten timber threshold (part of the door frame). Replacing it with a Stormguard aluminium cill should give vastly enhanced proofing against water entry. The refitted door will finish just over 1 brick course lower and I intend to rebuild the soldier brickwork course over the door as packing the gap above the new frame might look a bit naff.

I've sort advice elsewhere. Result:

The single brick garage is around 40 years old and the door frame was built into the wall using the horns. Horns are formed by cutting cill and top rail timbers at 45 deg to fit into the brickwork at each corner of the door. That made the frame an integral part of the wall. SFAIUI that method of fixing window and door frames was going out about then and being replaced by the current practice of screwing or bolting the frame into the brickwork openings. Timber used in the traditional method was generally of better quality and larger cross section than now and allowed the top rail to be used to support brickwork.

The new method has the advantage of easier fixing and replacement but as the timber is weaker it cannot support brickwork, hence the need for a lintel. IG and Birtley make suitable L shaped lintels around

100 x 100 in section.

Both makes advise the use of a DPC with the lintel. I had assumed this was to protect the lintel galvanized finish. Not so - the recommendation is for when the lintel is used in a cavity wall in association with a different lintel on the other leaf. As it is being used in structure exposed on both sides to the atmosphere, no DPC is required in this application.

As for what the lintel should rest on - basically it rests on the brick pillars either side of the door. A smeer of mortar under each side can be used to help spread the load, but essentially the lintel is built into the wall by starting the next brick and mortar course on the lintel.

HTH