Hello dear forum members,
The boss asked me to build a WPC deck. Currently, there is still grass growing there. The area measures 4 x 5 m (13 x 16 ft) and starts from the patio door. I am only concerned with the foundation.
This is what I have planned:
1. Dig to a depth of about 30 cm (12 inches).
2. Lay a geotextile membrane.
3. Spread a 20 cm (8 inch) layer of crushed stone, compacted with a plate compactor, with a 4% slope.
4. Add a 10 cm (4 inch) bedding layer of fine crushed stone, compacted again, with a 2% slope.
On this, I want to place individual rows of concrete edging stones, on which I can install the substructure.
I also plan to edge the whole area to prevent lateral slipping.
So far, so good. This also complies with the manufacturer’s specifications. Then a representative from a landscaping company came to make me an offer and said that he would never do it without concrete and reinforcing mesh and that he could not guarantee the work if done the way I am planning.
As I said, I wanted to do it myself anyway, but now I am a bit unsure.
Please share your opinions and knowledge on this subject.
Thank you in advance and have a nice weekend!
The boss asked me to build a WPC deck. Currently, there is still grass growing there. The area measures 4 x 5 m (13 x 16 ft) and starts from the patio door. I am only concerned with the foundation.
This is what I have planned:
1. Dig to a depth of about 30 cm (12 inches).
2. Lay a geotextile membrane.
3. Spread a 20 cm (8 inch) layer of crushed stone, compacted with a plate compactor, with a 4% slope.
4. Add a 10 cm (4 inch) bedding layer of fine crushed stone, compacted again, with a 2% slope.
On this, I want to place individual rows of concrete edging stones, on which I can install the substructure.
I also plan to edge the whole area to prevent lateral slipping.
So far, so good. This also complies with the manufacturer’s specifications. Then a representative from a landscaping company came to make me an offer and said that he would never do it without concrete and reinforcing mesh and that he could not guarantee the work if done the way I am planning.
As I said, I wanted to do it myself anyway, but now I am a bit unsure.
Please share your opinions and knowledge on this subject.
Thank you in advance and have a nice weekend!
Hi,
Oh, isn’t that the wood also known as ironwood? I thought it didn’t even float?! That’s quite impressive.
What beam thickness did you use?
Bongossi doesn’t seem exactly cheap either. For 80 x 80 mm (3 x 3 inches) beams, I’ve seen prices around 8-9 €/meter.
That’s roughly the price you’d pay for an IPE 80 profile steel beam. That’s why my basic idea is to use steel beams for the bottom, load-bearing layer. Then you could lay wooden cross beams on top, which in turn would support the actual decking boards.
Best regards,
Andreas
I chose Bongossi, which is also used for boat docks or livestock fences, as it performs extremely well with constant water exposure.
Oh, isn’t that the wood also known as ironwood? I thought it didn’t even float?! That’s quite impressive.
What beam thickness did you use?
Bongossi doesn’t seem exactly cheap either. For 80 x 80 mm (3 x 3 inches) beams, I’ve seen prices around 8-9 €/meter.
That’s roughly the price you’d pay for an IPE 80 profile steel beam. That’s why my basic idea is to use steel beams for the bottom, load-bearing layer. Then you could lay wooden cross beams on top, which in turn would support the actual decking boards.
Best regards,
Andreas
N
nordanney13 Apr 2016 08:19andimann schrieb:
Ah, isn’t that the material also known as ironwood? I thought it wouldn’t even float?!?
That’s definitely impressive. Yes, it actually sinks
andimann schrieb:
What beam thickness did you use?
Bongossi doesn’t seem exactly cheap either. For 80 x 80 beams, I see prices around 8-9 €/meter. I used 60 x 60. It was about €3.5 per meter. But I had to pick it up from a timber wholesaler in Bremen. In the Hamburg / Bremen area there is a large supply of wood because of the ports. They also tried to sell me Ipe decking boards – they had thousands of square meters in stock
andimann schrieb:
That’s why my basic idea was to make the lowest, load-bearing layer out of steel beams. On top of that, you could lay a cross layer of wooden beams, which in turn would support the actual decking boards. Exactly, you can do it like that. But then you need the steel beams AND the wooden beams on top.
nordanney schrieb:
You will then need both the steel beams AND the wooden joists again. However, you will also have to decouple the wooden joists from the steel beams; otherwise, they will rot. If I understand correctly, that would be unnecessary and double the work. Why not use a supporting beam made of larch or Douglas fir? If properly installed, it will last forever.
Back to the topic of slope regardless of type: I have a few more questions:
1. Will you see the fabric or the concrete curing bags through the joints afterward (mine are specified by the manufacturer as 8mm (0.3 inches))?
2. How do you manage the transition between the terrace and the lawn? Should an L-shaped concrete edging profile be installed at the lawn edge as a clean finish?
3. How do I adjust the surrounding lawn area to the slope? What I mean is: even if I create only a 1-2% slope and the terrace is, for example, 6 m (20 feet) wide, it would effectively be “hidden” below the surrounding lawn edge…
I hope what I’m asking is clear and not too complicated. Thanks in advance and greetings from Canada….
1. Will you see the fabric or the concrete curing bags through the joints afterward (mine are specified by the manufacturer as 8mm (0.3 inches))?
2. How do you manage the transition between the terrace and the lawn? Should an L-shaped concrete edging profile be installed at the lawn edge as a clean finish?
3. How do I adjust the surrounding lawn area to the slope? What I mean is: even if I create only a 1-2% slope and the terrace is, for example, 6 m (20 feet) wide, it would effectively be “hidden” below the surrounding lawn edge…
I hope what I’m asking is clear and not too complicated. Thanks in advance and greetings from Canada….
N
nordanney2 May 2016 09:40baudu schrieb:
1. After completion, can you see the fleece or the concrete freeze protection bags through the joints (mine are specified by the manufacturer as 8mm)? Our joints are narrower. You don’t see anything at all, just darkness.
baudu schrieb:
2. How do you handle the transition from patio to lawn? (Should an L-shaped concrete edging profile be installed along the lawn edge? Basically as a clean finish.) That depends on personal preference. So far, we have chosen for the patio to always be higher than the lawn. The edge is finished either with vertically installed planks or, currently, with a border of anthracite-colored concrete edging stones.
baudu schrieb:
3. How do I adapt the surrounding lawn area to the slope? I don’t quite understand the question. Either the patio is slightly higher than the lawn, then you have no problem at all.
However, if you want barrier-free access to the patio—that is, the same level as the lawn—then you actually don’t need to adjust anything. It just needs to be clear during the earthworks that the lawn area must be slightly lower than the start of the patio.
Thanks for the help and sorry for the late reply! We currently have paving stones in front of the patio door, which border the lawn. The new patio will be larger and will cover both the paving stones and the lawn. Unfortunately, it can’t simply be placed on top because the build-up height would then exceed the door threshold. So, I need to remove the paving stones and dig a “trench” into the lawn to achieve the necessary build-up height and a slight slope.
And here is my question: The patio will then be somewhat recessed compared to the surrounding lawn—not exactly flush with the ground, but also not fully raised on a substructure. How should I handle the lateral ventilation? Is it not very important? Or would it be better to remove enough of the surrounding ground so that the patio fully rests on the base and is ventilated on all sides?
Is that a bit clearer now?
Best regards from Boston
And here is my question: The patio will then be somewhat recessed compared to the surrounding lawn—not exactly flush with the ground, but also not fully raised on a substructure. How should I handle the lateral ventilation? Is it not very important? Or would it be better to remove enough of the surrounding ground so that the patio fully rests on the base and is ventilated on all sides?
Is that a bit clearer now?
Best regards from Boston
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