Jack the Lad

This weekend I have been taking out some old, badly cracked and corroded, concrete lintels and replacing them with extra heavy duty steel lintels from Stressline. The concrete had blown off the reinforcing irons and they were bowing so much that they touched the window frame in the middle. I approached the job with my customary optimism (assuming it would take half as long as it did) because I thought these 50 year old bits of crumbling concrete wouldn't put up much of a fight but they proved to be heavy weight champions. To add to the problems the outer course of bricks had also dropped and we had to jack them back into place so we could get the lintel clear without bringing down a large triangle of brickwork.

The problem with doing any job of this nature is that you have to strike a balance between accessibility and supporting the building. If you put too many Acrow steel jacking props in you can't get the old lintel out and the new one in. If you don't put in enough then you risk having some unwanted movement in the structure.

When it came to the point where we were going to drop this 300kg of concrete we knew that it would take the Acrows with it if it fell the wrong way. We were using Strongboys, which are cantilever plates that fit on the Acrows. These can support inner and outer skins at the same time if they are close in. But once we had nudged the lintel out to its critical balance point we then had to transfer the Strongboys to the inside of the building. Moving Acrows around is a pain. They aren't the easiest things to operate and if they have been stored in the open they tend to be a bit rusty which stops them operating smoothly. So far nobody has come up with a better design for adjustable steel props and I have a feeling that I might be retired by the time they do.


Once the old lintel was out it was very easy to lift the steel into place and jack it up (more Acrows tight under the floor joists. At this point I like to put the pressure on so the building lifts ever so slightly. That way if there is any shrinkage in the sand and cement bearers at least it will sit back where it was in the first place.
The usual trick is to build up the courses and leave them to go off overnight and then dry pack the last course before pointing it in as if it were ordinary brickwork.
Once the lintel was in place we intended to enlarge the window opening and put in a patio door. With the lintel still being supported by the jacks we decided to leave the window installation until next week. There is no sense in rushing these jobs.

Working all weekend also gets harder as you get older. At one stage of my life I could work ten days without a day off and think nothing of it but now getting up on the Monday morning after a full weekend of work comes hard. Is someone trying to tell me something?


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