sagging lintels?

Discussion in 'Builders' Talk' started by cs, Aug 18, 2007.

  1. cs

    cs New Member

    This house has 10 windows, all replaced 3 years ago with uPVC windows. On a 20 year old breeze block part, the rendering is cracking, so is inside plaster work. On the old stone bit there is no cracking. The insurance surveyor says that the metal lintels which were built for the wooden windows are not strong enough for the weaker uPVC frames, so are sagging.

    So, in other words, house insurance wont pay up (the small print problem). Window company's insurance might take the opposite view!

    Has anyone heard of lintels sagging because of a change from old wood to new uPVC? Watching the installers levering in the new with crowbars etc, could that have triggered the cracking in the weaker (new) part of the house? Id be very grateful for any other examples and views.
     
  2. ProDave

    ProDave New Member

    This is a common problem with Bay windows. Often the wooden window frame partly supports the upper bay and roof. A good window company will fit UPVC windows that have steel reinforcing bars embeded inside the UPVC frame.

    But I assume your windows are not bays, just a straight window in a straight wall. In which case what you have is very unusual.

    What span is the window opening and what type of lintel?

    Could be the insurance loss adjuster just trying to pass the buck to wriggle out of the claim. Try employing an independant structural engineer to determine the exact nature of the problem, and if he say's it's not the windows, go back to your insurance company. If he say's it is the windows, persue a claim from the window company.
     
  3. bigjules

    bigjules New Member

    This house has 10 windows, all replaced 3 years ago
    The insurance surveyor says that the metal lintels
    s which were built for the wooden windows are not
    strong enough for the weaker uPVC frames, so are
    sagging.

    The material from which the windows are made has no influence on the strength of a lintel. Lintels are designed to support masonry above an opening, whether it be filled with a window, door frame or nothing at all.

    Has anyone heard of lintels sagging because of a
    change from old wood to new uPVC?

    No. (Apart from structural bays as previous post).


    Watching the installers levering in the new with <u>crowbars</u>

    Go on, tell us installed the windows..........did they have stetsons??

    As previous post, spend a few quid and get your property structurally surveyed and then decide upon a course of action dependant upon the surveyors report.
     
  4. cs

    cs New Member

    Thank you both for good advice. I will get my own surveyor.

    The largest window span is 2 metres. None are bays.

    As for who installed them, and whether they wore stetsons, well, I'd better get them onside (if I can) before publicising that! The window company appeared to use 'freelance' or external installers, so there is another link in a buck-passing chain! (Which may answer your question in fact.)
     
  5. Mr. Handyandy

    Mr. Handyandy Screwfix Select

    My guess is the 'lintels' are no more that metal flat bars, say 7mm thick, in which case the windows should have been reinforced, and packed solid at uprights. If not, that is why they are dipping. Even with reinforcement, if they are not tight at the uprights, the reinforcing is next to useless.
    Some fitters have never heard of this.



    Mr. HandyAndy - really
     
  6. Mr GrimNasty

    Mr GrimNasty Active Member

    if they are not tight at the uprights,
    the reinforcing is next to useless.

    Mr. HandyAndy - really

    Caution: Dangerously inept advice.
     
  7. Mr. Handyandy

    Mr. Handyandy Screwfix Select

    if they are not tight at the uprights,
    the reinforcing is next to useless.

    Mr. HandyAndy - really

    Caution: Dangerously inept advice.




    How so ?

    If a reinforcing bar is put inside the upright of the window frame, but is not packed tight under and over the position of the upright, then the bar is of no use whatsoever. The whole frame will dip.

    Kandy, explain.



    Mr. HandyAndy - really
     
  8. Mr. Handyandy

    Mr. Handyandy Screwfix Select

    Come on Kandy. Explain your derogatory remark.


    Mr. HandyAndy - really
     
  9. Mr GrimNasty

    Mr GrimNasty Active Member

    Come on Kandy. Explain your derogatory remark.

    (a) It was not derogatory.
    (b) I don't have to explain myself - the shortcoming in your advice is blindingly obvious.
    (c) I have a new policy of not entering into arguments with you because it ruins the thread/forum for everyone.

    The correct advice in this situation is: put in adequate lintels.
     
  10. sinewave

    sinewave Screwfix Select

  11. Mr. Handyandy

    Mr. Handyandy Screwfix Select

    Come on Kandy. Explain your derogatory remark.

    (a) It was not derogatory.




    It most certainly WAS derogatory. "Dangerously inept advice" is MOST derogatory.


    (b) I don't have to explain myself - the shortcoming
    in your advice is blindingly obvious.


    Yes you DO have to explain yourself, because you are telling the OP that my advice is wrong. You should(if you can) say WHY it is wrong.(You can't because it isn't)



    (c) I have a new policy of not entering into
    arguments with you because it ruins the thread/forum
    for everyone.



    It ruins the thread when people give WRONG advice, which in this case AGAIN, is yourself.




    The correct advice in this situation is: put in
    adequate lintels.


    And my advice was that a properly reinforced window, that is also well supported, MAY have been sufficient(without seeing and calculating loads, no-one here knows). But a window with reinforcement bars, but NOT supported, may NOT be sufficient.


    Kandy, you have to give some input into the reasons that THIS is 'dangerously inept advice'.

    Put up, or shut up, as they say.






    Mr. HandyAndy - really
     
  12. Mr GrimNasty

    Mr GrimNasty Active Member

    Take a chill pill dill.
     
  13. 12benny

    12benny New Member

    Take a very careful look at the window head(s) to determine if they have indeed
    got "metal" lintols or any lintols. Steel rsj's dont sag - flimsy section(thickness) wooden lintols might sag.
    Replacement frame companies are notorious for the damage they create.
    Old wooden frames often had a supporting mullion in the centre and when the frame is removed can cause cracking above the opening.
     
  14. ukthundercat

    ukthundercat New Member

    to the best of my knowledge, no upvc window is load bearing unless it is a bay with bay pole jacks, and unless installed properly these can even be iffy.

    when installing a upvc window, an expansion gap of at least 5mm should be left all around the frame accept at the cill to allow for expansion. so if the frame were to be packed solid to help support loads from above it wouldn't be able to expand properly and also would probably not be installed to manufacturers specification.

    answer would be to install correct lintel.
     
  15. joinerjohn1

    joinerjohn1 Screwfix Select

    As someone pointed out earlier. the lintel should support the brickwork above any opening.(whether there's a window, door or nothing in the opening) On some older houses the wooden windows were built in as the brickwork went up, and so supported the bricks above. However the OP says there are lintels supporting the brickwork. Assuming these are supporting the brickwork, then the UPVC windows have no bearing on whether the render is cracking or not.
    Someone mentioned easing the windows in using crowbars (and Stetsons as headwear in the same sentence). I can assure you it's quite common to use a variety of tools to aid the positioning of windows into openings, (crowbars, prise bars, chisels etc) to ensure it's final position is correct, although it's more common for headwear to be a  hard hat. ;)
     
  16. Mr. Handyandy

    Mr. Handyandy Screwfix Select

    Sorry mate. The 5mm gap is for positioning and squaring. As with most existing openings, if a new window is cut to exact measurements, and the opening is not square, the fitted window/door will not ever be square.


    Mr. HandyAndy - Really
     
  17. joinerjohn1

    joinerjohn1 Screwfix Select

    Handy, the 5mm clearance will make no difference if the opening is a mile out of square. I had to fit a new wooden window into an opening which was quite a bit out of square (even though the measurements of the opening were the same top to bottom at right middle and left  and similar across the width, the opening formed a trapezoid shape rather than an oblong) Took a lot of planing down to make the window fit the opening (and for the window to remain square for the glazing units) Lucky it was a wooden window though. Still looked noticeably wrong when fitted, even though the window was plumb and square. ;)
     
  18. A lot of the older houses including local authority houses were built with no lintol carrying the outer skin.
    Some relied on a cast in situ concrete boot lintol which did offer some  support to the outer wall.
    Most windows then were Crittall windows, much stronger, and sometimes set in timber frames.

    The window company should have done a survey prior to pricing and fitting new upvc windows, they are not designed to take the weight.

    We have undertaken quite a few jobs like this, where the windows were replaced without checking ( or caring ) wether there is a lintol in place.
    Over the time, the outer skin has dropped causing bowing to the heads of frames, and in some instances cracking the glass.
    The only remedy is, acros and strong boys, remove three courses of bricks, insert new lintol. a cavity tray should be fitted at the same time.
    In hindsight all of this should have been done prior to fitting new windows by a team of brickies.
    I cant believe some of you have never come across this, its pretty common sense, as for the fitters they should have noticed this when removing existing windows.
    They were probably on a fixed cheap price and just fired them in and collect the cheque.
     

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