Window Lintels

[john.moxon]

Hi Guys

I bought a 1940's semi 5 years ago & The previous owners of the house had the windows replaced from wood frames to UPVC.

Several months ago I noticed a crack develop on the outer wall above both sides of the living room window. The window is approx 2.3m wide. The cracks have continued up 10 courses of bricks in a triangle pattern and meets at a point about 3-4 bricks below the upstairs window.

There are no cracks on any of the internal walls and from replastering the living room 2 years ago i definitely know there is an internal lintel.

Would you say the cracks are due to a missing external lintel.

How much approx does this kind of job cost to rectify.

Do i need to get a special kind of tradesman to do the work or will a General Builder or Brickie be able to carry out the wrks.

 

[Shytalkz]

Would you say the cracks are due to a missing external lintel.

Yes, covered extensively on the forum, use the search facility and all will be revealed!

 

[sandwell]

I have exactly the same problem. I have searched the forum, but not found the answer. Is the plastic window sufficient to support the brickwork for a long time, or should the window be removed, and a lintel inserted.
Be grateful for any advice please.

 

[Shytalkz]

Upvc is not designed to take load, with the exception on bay windows, where bay poles are inserted between the frame sections, which in themesleves are not generally very widely spaced.

Older places with cavity walls were often built with the window in place, the outer leaf sitting on the window frame, which has greater load-bearing cability than a flimsy bit of plastic. Sometimes the outer leaf is tied to the inner leaf; sometimes not. It is not possible to tell, without invasive investigation.

The disturbance in removing the existing windows can sometimes break whatever bond there is that gives support to the outer leaf in addition to the original window frame. For short openings, that is unlikely to result in a problem with Upvc windows, however.

If the brickwork can't "arch" over the opening and there is no adequate other form of tie to the inner leaf and the opening is relatively wide (in my experience 1200 or more), then the load will transfer to the window frame, this can deflect and lead to cracking above the opening; in extreme cases with a considerable load, the glass can distort and even fracture. Sometimes, there are wide openings, but only a short distance between the upright sections of the window and the plastic top section of the frame doesn't deflect unduly.

It is a problem which should be picked up when the windw company do their survey, but generally isn't. If support is needed, it depends on the arrangement that exists, but can include installing a new lintel to support the outer leaf only, or retro-fitting additional wall ties.

Tends to be less problematic with solid wall construction, as there is not two separate leaves of masonry.

John's window definitely needs a lintel. A competent general builder can do this work, no problem.