Hi,
I would like to have a small shed in my garden to store my lawn mower and other equipment. Do I need a foundation for it, or can I place it directly on the grass? I have no experience with this and would appreciate any helpful advice!
I would like to have a small shed in my garden to store my lawn mower and other equipment. Do I need a foundation for it, or can I place it directly on the grass? I have no experience with this and would appreciate any helpful advice!
Hello Schakal,
A reinforced concrete slab is certainly very stable but requires significantly more effort. Underneath a reinforced concrete slab, there should be at least a capillary-breaking layer (20cm thick gravel layer) to prevent frost damage and cracking.
For a garden shed measuring 3.00 x 4.00m (10 x 13 feet) with a slab thickness of 10cm (4 inches) as you mentioned, you would need to prepare 1.2m³ (42 cubic feet) of concrete. That corresponds to about 15 wheelbarrow loads of standard size (80 liters (21 gallons)) each. Additionally, you would need twice the amount of the gravel mentioned above. That’s quite a bit of work, even if you have ready-mixed concrete delivered. A slab flooring or paving would be much quicker to install.
Also, with a shed that has its own floor, no weeds can grow underneath because no light reaches there and it tends to be quite dry below.
A reinforced concrete slab is certainly very stable but requires significantly more effort. Underneath a reinforced concrete slab, there should be at least a capillary-breaking layer (20cm thick gravel layer) to prevent frost damage and cracking.
For a garden shed measuring 3.00 x 4.00m (10 x 13 feet) with a slab thickness of 10cm (4 inches) as you mentioned, you would need to prepare 1.2m³ (42 cubic feet) of concrete. That corresponds to about 15 wheelbarrow loads of standard size (80 liters (21 gallons)) each. Additionally, you would need twice the amount of the gravel mentioned above. That’s quite a bit of work, even if you have ready-mixed concrete delivered. A slab flooring or paving would be much quicker to install.
Also, with a shed that has its own floor, no weeds can grow underneath because no light reaches there and it tends to be quite dry below.
Hello Daton!!
Thank you for your reply and your detailed answer. How you responded suits me well and is completely correct—you know your field—but for me, it’s a bit too theoretical, nothing personal. I don’t want to go into more detail.
I believe that a concrete slab can and will definitely hold up, and whether it requires more effort is debatable since we don’t know the site conditions.
I estimate one wheelbarrow, 18 bags of gravel, and let’s say 10 bags of cement for reinforcement.
I can’t quite agree with you about the weeds; nothing might happen, but what about the outside area around the shed, ground, etc.? Water could also accumulate there, right?
Also, I believe no heavy machinery will drive over the concrete slab, but rather loads of around 50 to 150 kg (110 to 330 lbs) will be applied.
I think the effort and naturally the cost would be lower.
But it doesn’t matter—each has their own opinion, and that’s good, so no hard feelings…
Best regards.
Thank you for your reply and your detailed answer. How you responded suits me well and is completely correct—you know your field—but for me, it’s a bit too theoretical, nothing personal. I don’t want to go into more detail.
I believe that a concrete slab can and will definitely hold up, and whether it requires more effort is debatable since we don’t know the site conditions.
I estimate one wheelbarrow, 18 bags of gravel, and let’s say 10 bags of cement for reinforcement.
I can’t quite agree with you about the weeds; nothing might happen, but what about the outside area around the shed, ground, etc.? Water could also accumulate there, right?
Also, I believe no heavy machinery will drive over the concrete slab, but rather loads of around 50 to 150 kg (110 to 330 lbs) will be applied.
I think the effort and naturally the cost would be lower.
But it doesn’t matter—each has their own opinion, and that’s good, so no hard feelings…
Best regards.
F
Formfleisch6 Jun 2009 21:44Hello Danton,
the thread is closed for Schakal, but I find your explanations very convincing and hope I can keep the topic alive for a short time.
As a new garden owner, I found an extension on the existing stone shed, about 3x3m (10x10 ft), a fairly sturdy, covered but airy slatted structure. The four supports stand on isolated point foundations, about 60-80cm (24-31 inches) deep, with 30x30cm (12x12 inches) concrete slabs inside laid directly on the earth and quite uneven.
Plan:
Use the existing foundations and completely rebuild the extension, well insulated so it can be heated during transitional seasons without significant heat loss.
Although a reinforced concrete slab would be the easiest and cleanest solution, I prefer to lay the small slabs again because
- hauling so much building material is annoying
- such a foundation requires a building permit / planning permission
- it would be a hassle to ever dispose of the slab again (leased garden!)
In the attic of the stone shed, I found about a 10cm (4 inches) thick, crumbly screed layer (around 1 cubic meter) - looks a bit like blast furnace slag, ranging from 1-2cm (0.4-0.8 inches) sized pieces to very fine dust. Probably a post-war improvisation...
Additionally, I demolished an older foundation of a former shed, resulting in another half cubic meter of rubble (pieces up to about 5cm (2 inches) in size).
1. Question:
Wouldn't it make sense to reuse this material under the concrete slabs instead of ordering a container for disposal (first a layer of rubble, then fine slag on top, then compact)? Or does it have to be gravel?
2. Question:
Since the room will have a wooden floor (kitchen), should I lay a PE foil (pond liner?) on top of the concrete slabs and then timber sleepers and boards? Do I need to worry about condensation from below? And if I provide sufficient ventilation underneath, how do I insulate the floor against cold (baby crawling around...)? Insulation boards?
When other forums discuss loose slabs, you rarely find out what happens next.
Thanks for any answers,
Sebastian
the thread is closed for Schakal, but I find your explanations very convincing and hope I can keep the topic alive for a short time.
As a new garden owner, I found an extension on the existing stone shed, about 3x3m (10x10 ft), a fairly sturdy, covered but airy slatted structure. The four supports stand on isolated point foundations, about 60-80cm (24-31 inches) deep, with 30x30cm (12x12 inches) concrete slabs inside laid directly on the earth and quite uneven.
Plan:
Use the existing foundations and completely rebuild the extension, well insulated so it can be heated during transitional seasons without significant heat loss.
Although a reinforced concrete slab would be the easiest and cleanest solution, I prefer to lay the small slabs again because
- hauling so much building material is annoying
- such a foundation requires a building permit / planning permission
- it would be a hassle to ever dispose of the slab again (leased garden!)
In the attic of the stone shed, I found about a 10cm (4 inches) thick, crumbly screed layer (around 1 cubic meter) - looks a bit like blast furnace slag, ranging from 1-2cm (0.4-0.8 inches) sized pieces to very fine dust. Probably a post-war improvisation...
Additionally, I demolished an older foundation of a former shed, resulting in another half cubic meter of rubble (pieces up to about 5cm (2 inches) in size).
1. Question:
Wouldn't it make sense to reuse this material under the concrete slabs instead of ordering a container for disposal (first a layer of rubble, then fine slag on top, then compact)? Or does it have to be gravel?
2. Question:
Since the room will have a wooden floor (kitchen), should I lay a PE foil (pond liner?) on top of the concrete slabs and then timber sleepers and boards? Do I need to worry about condensation from below? And if I provide sufficient ventilation underneath, how do I insulate the floor against cold (baby crawling around...)? Insulation boards?
When other forums discuss loose slabs, you rarely find out what happens next.
Thanks for any answers,
Sebastian
Hello Formfleisch,
if you want to use the construction debris, you need to screen it first.
You should only use particle sizes of at least 1 to 2cm (0.4 to 0.8 inches). The finer the material, the stronger the capillary action.
You can also use gravel or recycled material as a capillary break layer, but it should be coarse-grained.
On top of that, a layer of gravel that can be leveled smoothly, so you can lay the concrete slabs on it.
As a moisture barrier, do not use a continuous sheet; instead, place roofing felt only under the sleepers, because otherwise any moisture that forms might not be able to drain through the joints of the concrete slabs.
I have attached a simple cross-section drawing. From this, you should be able to understand my suggestion more clearly.
Around the sleepers, you should install perforated metal sheets or something similar to prevent pests from getting under the shed.
How do you plan to heat the space? Keep in mind that during freezing periods, water-carrying pipes in unheated rooms should be drained.
For this reason, a small electric heater would be a suitable option here.
if you want to use the construction debris, you need to screen it first.
You should only use particle sizes of at least 1 to 2cm (0.4 to 0.8 inches). The finer the material, the stronger the capillary action.
You can also use gravel or recycled material as a capillary break layer, but it should be coarse-grained.
On top of that, a layer of gravel that can be leveled smoothly, so you can lay the concrete slabs on it.
As a moisture barrier, do not use a continuous sheet; instead, place roofing felt only under the sleepers, because otherwise any moisture that forms might not be able to drain through the joints of the concrete slabs.
I have attached a simple cross-section drawing. From this, you should be able to understand my suggestion more clearly.
Around the sleepers, you should install perforated metal sheets or something similar to prevent pests from getting under the shed.
How do you plan to heat the space? Keep in mind that during freezing periods, water-carrying pipes in unheated rooms should be drained.
For this reason, a small electric heater would be a suitable option here.
F
Formfleisch9 Jun 2009 23:38Hello Danton,
Thank you very much for the quick and detailed response. After several days of fruitless Googling, the drawing is truly a blessing.
I suppose I can equip the stone alcove similarly: vapor barrier on the stone floor, insulation, OSB boards? Otherwise, the level difference is quite large, and back in ’48 they apparently didn’t give much thought to thermal insulation...
Regarding the question about heating:
Originally, I wanted to get the fireplace working again; the bricks were removed up to the ridge in the 1980s, and corrugated fiber cement sheets were installed on top. I was thinking of installing a small stove since firewood is already plentiful.
However, today I thought that if I insulate the floor and roof as planned, an electric heater might not be a bad idea after all. It delivers constant heat (especially at night). I just can’t really estimate how (un)efficient such a radiator would be...
Thank you very much for the quick and detailed response. After several days of fruitless Googling, the drawing is truly a blessing.
I suppose I can equip the stone alcove similarly: vapor barrier on the stone floor, insulation, OSB boards? Otherwise, the level difference is quite large, and back in ’48 they apparently didn’t give much thought to thermal insulation...
Regarding the question about heating:
Originally, I wanted to get the fireplace working again; the bricks were removed up to the ridge in the 1980s, and corrugated fiber cement sheets were installed on top. I was thinking of installing a small stove since firewood is already plentiful.
However, today I thought that if I insulate the floor and roof as planned, an electric heater might not be a bad idea after all. It delivers constant heat (especially at night). I just can’t really estimate how (un)efficient such a radiator would be...
Hello Formfleisch,
a wood-burning stove is a great option, especially if you already have enough firewood available. For quality reasons, I would recommend choosing a branded stove from a specialized retailer. A stove with 6 to 7 kW is more than sufficient for heating over 100m² (1,076 sq ft) of living space.
It is very important to first consult with the chimney sweep (certified chimney technician) to find out which regulations must be followed.
By electric heater, I meant those small portable units on four wheels from the hardware store, not the heavy ones with fireclay bricks (storage heaters) inside.
You could also use both options.
Attached is an alternative to a garden shed made of masonry.
a wood-burning stove is a great option, especially if you already have enough firewood available. For quality reasons, I would recommend choosing a branded stove from a specialized retailer. A stove with 6 to 7 kW is more than sufficient for heating over 100m² (1,076 sq ft) of living space.
It is very important to first consult with the chimney sweep (certified chimney technician) to find out which regulations must be followed.
By electric heater, I meant those small portable units on four wheels from the hardware store, not the heavy ones with fireclay bricks (storage heaters) inside.
You could also use both options.
Attached is an alternative to a garden shed made of masonry.
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