spalled lintels

[vansbest]

Hi, I have a No Fines constructed house and both ground floor window lintels have spalled on the bottom edges. I reckon they could be repaired using epoxy but think it may be better to replace. The lintels are precast concrete ( with 2 fairly hefty twisted rebars) both 80 high x 180 deep and 2.1m and 2.8m long respectively . The first floor joists run parallel to the lintels. I'm assuming, since the main structure is concrete (albeit NO Fines) that I would still be best to use a couple of Strong Boys and props to support the concrete above the lintels. I would place these in the mortar joint between the lintel and the concrete. If this sounds o.k. how long should the props be left in position?
Many thanks

 

[tony1851]

The no-fines houses are difficult to work on. The walls are OK if left alone, but once you start cutting and supporting, you need to be very careful.

On a 2.1m span, I would be inclined to add at least a 3rd strongboy. The concrete can be crumbly and there will be considerable pressure on it if it is just supported at 2 points. The 2.8m span is even more problematic; your method of support needs to be carefully considered.

Once your new beams are in, how are you going to ensure that the wall above is adequately supported on them? You would be best supporting the beams temporarily and carefully grouting up the gap between the top of the beam and the underside of the no-fines.

If the beams seem still sound, and the rebars OK, would it not be easier to do the epoxy repair instead?

 

[Nige F]

Agree with Tony - particularly as the floor joists are paralell . Google concrete cancer repairs and post a pic. if you like , there may be a way to keep the rain off the lintel with a cast above or a reformed drip under . etc.

 

[^woody^]

Structural work to no-fines properties is specialist, and replacing a lintel is not the same as replacing a lintel on a traditional house

So get some specialist advice from a structural engineer experienced with no-fines

 

[vansbest]

Hi, and thanks for the responses and valuable advice.
I have had a closer look at these lintels. The sizes are 250 x 250 ( I thought they seemed a bit thin and lightweight ) The spalling on the longest lintel is over a 2m length, at the bottom, with approx 80mm thickness of concrete displaced across the width of the lintel. Hopefully my pics show this clearly. In light of this would you advise that I engage the services of a professional concrete repair company. Certainly seems that if a repair is possible, this would be the way to go rather than replacement.

 

[vansbest]

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• vansbest
• 23 Jul 2012
• 1

Untitled

• vansbest
• 23 Jul 2012
• 1

Untitled

• vansbest
• 23 Jul 2012
• 1

 

[^woody^]

Oh dear, I never though you meant inside, and to that extent.

Yes, I think you definitely should get these professionally looked at by a structural engineer, or a specialist repairer