Fixing a cement slab that’s breaking up requires more than a screed
I SPENT last weekend making two garden gates. I am very proud of my handiwork, as I am not great with my hands, but with a few simple tools and a bit of thought I had a great time by attempting something different. I actually did something for me and can highly recommend the experience to everybody. Tip of the week
If you’re looking for ways to save on your electricity or gas bills in the cold weather, here’s some advice.
As a semi-retired person learning to count his pennies, I’ve realised it is cheaper to add a few layers of clothing than it is to switch on the heaters.
To ensure that the bed is nice and warm, invite the dogs in for a little sleep-over, but not for the whole night as you don’t want to be fighting over blanket ownership at 2am, but every little bit helps. Questions and answers
I am getting more and more requests asking for help when things have gone wrong with one’s contractor.
I am willing to help where I can, but I’ll need copies of the quotations you accepted and a copy of the contract you signed. As I have said, if you don’t start off with the correct paperwork, then you are not going to have a leg to stand on.
Liz wrote: “Last week’s column was especially rewarding for me as I am in the market to purchase a property. Where do I source a ‘home inspector’? I am looking at a property in Fish Hoek and will feel a lot more re-assured if an inspection is done at my expense.”
Contact John Graham of House Check on 083 310 9766 or e-mail firstname.lastname@example.org; he is a regular correspondent of mine.
Gaye asks: “I was very interested to read about the applications for occupancy and have a question: When it says the building must comply with the approved building plans, what if some part of the building does not comply? I refer to an exterior staircase and landing which does not comply with the approved plans as it was built in the incorrect location, and is part and parcel of the building.”
I cannot answer this myself, but have forwarded the question to Cheryl at the City of Cape Town and will hopefully have an answer for you by next week. Off the top of my head, I would guess that the answer will revolve around how far out of position it is, and whether it can still safely provide the function for which it was intended while complying with the necessary regulations applying to emergency exits.
Eddy writes: “I have an old, and breaking up, cement slab on my stoep. I now wish to re-lay a cement screed on top, after I have chipped and prepared the surface. The area is 25m What is a general rule of thumb relating to the amount of cement and sand required? Also, I am thinking of a screed of approximately 100mm – is that about right? The pedestrian traffic over the completed screed would be minimal –just my wife and myself and the odd visitor.”
My initial advice is not to lay a new screed on top of a slab that is already breaking up. Chipping the surface as you propose is a good idea as a start, but if the slab is in poor condition, it is just going to take the new screed with it as it continues to sink and crack.
I would recommend that you get a structural engineer to give an opinion as to whether the slab has reached the end of its life. If it is already cracked, the chances are that water has seeped through and eroded the filling underneath. It may then be cheaper to put down a new slab that could possibly be powerfloated to give an acceptable finish.
There are far too many rules of thumb about what mix is the best for what; I would suggest that you consult one of the cement companies’ websites, where they give all the recommended mixes for different applications.
It is not often that a screed is laid thicker than 25mm to 35mm, unless you are trying to create a specific fall over a small area.
If you want a more trafficable finish, then I would suggest a grano screed – this is where small granite chips are added into the mix to add strength and hardness, but to me 100mm shows a need for concrete and
not a cement screed. Company of the week
I don’t often praise individual concerns but two companies and the women responsible for sending out quotations really impressed me today.
I have been helping out my old company with some tendering and sent out a document asking for prices at 6am one day. I received my first reply at 11am for the materials involved and the follow-up quote at noon. So a big bunch of roses to Angelica at DBL precast decking systems and Carmelita at Devco Decking solutions.
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