The free diy home improvement guide with answers to your questions on a wide range of do it yourself projects.


Breaking up the Concrete and Garden Wall

Previous Stage
Reclaiming Bricks

With most of the brick walls of the old extension demolished, work begins on breaking up the old concrete slab forming the floor. Because demolition of the flank wall will have an effect on the neighbours, the builders – G L Smith and Sons from Hertfordshire - explain that this will be left in place until it absolutely needs to come down. It’s obviously good to see such consideration on a building site but, it also helps build and maintain their reputation. A little thought goes a long way.

The wall also seems to have no bricks that can be reclaimed so it will be used for hardcore under the new slab. Leaving it in place while the concrete slab is broken up and removed from site will mean that the wall can be demolished and placed as hardcore almost in one go.

most walls demolished water supply pipe

Towards the edge of the over site concrete you can see where the old water supply came in to the building. This will need to be worked around carefully to avoid damaging the pipe work. The water main also runs across the property beneath the slab serving the neighbours houses as well.

The slab is broken up using a hydraulic breaker. The point fitted to it makes reasonably light work of the slab and it’s soon a grid of broken concrete. A long wrecking bar is also used as it can be levered into the holes created by the breaker to further break up the slab. The long handle gives a lot of leverage force.

hydraulic breaker breaking up concrete clearing broken concrete

As one of the team works across the slab with the breaker, another starts clearing the concrete and barrowing it to the skip on the front drive. The skip has a drop front making the job of emptying the barrow a little easier. Filling the skip from the far end first capitalises on the benefit of the drop front.

drop door skip part filled

The broken concrete is in fairly sizeable pieces making it too big for the depth of hardcore required on this job. However, it’s already been worked out that there is enough hardcore available from the demolition of the old walls. Had this not been the case, the concrete could have been broken up further to make it useable rather than buying in new material. As one of the builders explained, reusing materials where practical and possible can save a fair bit of money on a job – but the extra cost in time to break up the concrete further isn’t always worthwhile.

While the slab is being broken out, a low level brick wall and planter are demolished. This is normally a simple job involving a few swings of a sledge hammer. However, after a couple of blows it becomes obvious it more solid that you’d expect and the builder suspects that some sort of reinforcement has been used to tie it in to the shared garden wall. As he explained, if you carry on hammering away at it, it’s likely to damage the garden wall. On further inspection, an old steel pole is revealed which ties the two together. This is cut away and the rest of the wall taken down. Where the brick was bonded into the garden wall, an angle grinder is used to cut it back flush.

reinforcement in garden wall thin concrete slab

With the slab which was once the kitchen floor broken up and removed, work starts on removing the remaining area of concrete where the new extension will be. This is mostly thinner than the floor as it’s a simple patio / paving area for the garden. As you can see in the pictures this is fairly piecemeal and some is made up of two layers but neither is particularly thick so it doesn’t take as long to remove.

If you live in the Hertfordshire area and are looking for a professional building contractor, you can get in touch with G L Smith and Sons via their website:

Previous Stage
Reclaiming Bricks

G L Smith and Sons