Garage and shed bases
A shed base is a small slab, and most domestic slabs of that kind are 100 mm thick. A garage that's part of the house is a ground floor under the Building Regulations: at least 150 mm of concrete on at least 200 mm of hardcore.
Work out the concrete as length × width × depth, and add 5 to 10% for uneven ground and waste.
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How much concrete a base takes
| Base | Area | At 100 mm | At 150 mm |
|---|---|---|---|
| 2.4 × 1.8 m | 4.32 m² | 0.43 m³ | 0.65 m³ |
| 3 × 3 m | 9 m² | 0.90 m³ | 1.35 m³ |
| 6 × 3 m | 18 m² | 1.80 m³ | 2.70 m³ |
| 6 × 6 m | 36 m² | 3.60 m³ | 5.40 m³ |
Shed and storage bases
For bike sheds, bin stores and timber sheds, a lean mix does: it compacts easily and gives a firm, level base for light buildings. Most shed bases are about 100 mm thick on a compacted sub-base, but follow the shed maker's drawing where there is one.
Garage floors
A garage attached to a house, or built as part of it, is a floor under the Building Regulations like any other: TGD C's ground-supported floor of at least 150 mm of concrete on at least 200 mm of hardcore, with the damp-proof membrane and the radon measures.
Slabs taking heavy loads need a higher strength and, outside, a brush finish. Inside, a power floated finish is the usual choice for a garage.
Bags for the small jobs
For a post or a very small base, bagged products save a delivery. What the materials cost:
| Price |
|---|
| €3.99 |
| €9.65 |
| €22.00 |
A rapid setting mix gives you about 10 minutes to place each batch. For a whole garage floor, ready-mix is the practical way: see ready-mix vs site-mixed.
Floors laid by the contractor who takes your call
Calls on this site ring JAM Floor Screeding: James Mulhall, based in Portlaoise, 25 years laying floors. Lines open Mon to Sat, 7am to 6pm. He pours concrete floors, slabs and foundations as well as screed. These are his jobs.
“JAM were punctual, professional and efficient and did an outstanding job on pouring our new floor as part of a renovation. Very highly recommend!”
“Excellent work, laser level finish, neat and tidy worker, highly recommend.”
“Top class work by james and his crew, highly recommend”
Quoted word for word from JAM Floor Screeding's Google reviews. Read them on Google
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Garage and shed bases questions
How thick should a shed base be?
Most domestic slabs such as shed bases and patios are 100 mm thick, on a compacted base. Follow the shed maker's drawing if it gives one.
How thick should a garage floor be?
A garage that's part of the house is a ground-supported floor under TGD C: at least 150 mm of concrete on at least 200 mm of hardcore, with the membranes.
How much concrete for a 3 m × 3 m shed base?
0.9 m³ at 100 mm, before adding 5 to 10% for waste. Our arithmetic. Ready-mix comes in loads from 1 m³.
What concrete for a shed base?
A lean mix suits shed, bike and bin store bases: it compacts easily and gives a firm, level base for light buildings.
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