Wooden Lintels

[rcs]

We have wooden lintels over each window and door in a 1920's house (9" walls) and are wondering what to do with them. One in particular is splitting/rotting so when it is replaced, should it be replaced with concrete/steel and should the BCO be involved?

Thanks

 

[noseall]

concrete builders lintels are generally used internally and only for certain loads or spans. for door sized openings at 900 mm or so, or larger spans but with less weight to carry, then concrete will be ok.

steel lintels are generally used on external scenarios and for larger loads or spans. also the thin leading edge of say a catnic lintel, makes them ideal on face brick work, as the thin edge becomes hardly visible.

any load bearing spans of 1800 or more, regardless of which type of lintel you use, requires calcs.

it would be wise to get a visit from b.c. to inspect the end bearings before you cover them up.

 

[^woody^]

There is no need to replace in concrete or steel, as properly sized timber lintel will do.

A concrete or steel one will have no initial shrinkage or seasonal movement, but a concrete one may cause a coldspot and local condensation, and a steel one may be more work to install.

There is no requirement to involve building control as this is maintenance, not new controlled work.

 

[rcs]

Thanks for your replies. So any rotten/decayed lintels can just be replaced with new timber and no BC required. What wood would I need to use and would I have to support the structure whilst I'm replacing them?
Ta.

 

[^woody^]

You should use stress graded (c16 or c24) and treated (tanalised or vac-vac), and if the current one has given no problems, then of the same size section.

However, for the minimal cost difference, most people would just bung a concrete one in nowadays and be done with it. If the lintel supports the external face as well, then a steel one would look better

Whether you need to support the wall above depends on the span and if it will stay up unsuported for a brief period of time (condition of wall), and what load is being supported by it.

 

[noseall]

if you have a typical 1920s house, then you will have a timber lintel internally with either masonry lintelling on the outside or brick work built directly onto the window frame.

by masonry lintelling i mean brickwork header forms with keystone or full stone lintel. these were typically used in conjunction with sash windows. as sash windows sit on the inner leaf.

whilst casement type windows or those that sit on the outer leaf, would typically have the bricks laid directly on top of the window.

have you had to, or are you going to be replacing the windows in the future?

 

[rcs]

We're planning on replacing the existing casement windows in the near future but as the outside is heavily rendered, I can't see how the outer course relates with the window. I'd prefer to go concrete though, just don't know how it's all going to work (acro etc) when we replace the windows and if the replacement windows would need to be structural.
Ta.

 

[noseall]

if you plan on replacing the windows in the near future, particularly if you are going to replace with upvc, i strongly recommend using a steel catnic or similar.

like this,