Substructure terrace
Terrace substructure: Tips and ideas for the ideal terrace construction!
Property owners with their own garden want a beautiful terrace. Many terraces are getting on in years, too small for the desired uses or damaged. As a rule, it is not that difficult to build a modern and durable terrace with your own resources. In this guide you will find out what you should pay attention to with such a substructure for the terrace.
Very important: With a terrace, it always depends on the respective underground situation. A terrace substructure thus forms the basis for maximum stability and durability of your new terrace. Therefore, you should give great importance to planning and let professionals support you more than necessary.
Clarify the visual appearance right at the beginning: What should the terrace substructure look like in the end?
First of all, you should decide what the terrace should look like later. As a rule, most use wood or WPC panels for the top cover. These materials not only look good, but are also easy to maintain and clean. The panels are available in numerous colors that you should ideally choose for your garden or your house.
Finally you have the opportunity...
- a rectangular terrace
- a square terrace
- an angled terrace
- a rounded terrace
to build. It depends on how you want it to fit into your garden.
If you later want to build a patio roof, you should also consider the foundation for the supporting beams. In this case, you would have to subsequently remove the top panels again and at the same time reinforce the substructure for the terrace at the points.
However, before you go to the top, visible cover, you need a solid substructure for the terrace.
The most common types of terrace substructure are:
- the wooden construction strips
- the aluminum substructure
- the WPC construction strips
The different types will be discussed in more detail later.
Terrace substructure – what you have to consider when it comes to the underground situation
With a substructure for the terrace, you should always consider the subsoil, which should offer a high level of stability if possible. In addition, the ground there is not always level, but can also contain indentations and inclines.
You can usually see how this floor really is when you have removed an old terrace. If possible, it is advisable to level the ground before erecting a substructure for the terrace.
Substructure for the terrace with grass, meadow and soil
If you have a softer subsoil of soil, grass or meadow below your terrace, you must first remove between 40 and 80 cm of soil. Be generous, as you will have to rework the edges later. Lay another thick sheet of weed fleece on the ground. Then you will have less trouble later with weeds growing up.
Pour 25 to 65 cm of gravel into this pit and compact it with a 15 cm thick layer of gravel. Shake everything firmly into the ground. Now you can set the foundation for the substructure for the terrace. Washed concrete slabs are usually sufficient here. However, this can be done more professionally with a strip foundation. If you want, you can also use foundation stones. These have roughly the same function as a terrace foundation.
If you use construction strips, then make sure to pay attention to the minimum dimensions. It depends on the length and width. So-called pedestals are now placed on the foundation. These are usually provided with a screw thread so that you can adjust the height here. Place a rubber pad on each plate to prevent slipping and dampening.
Now you can place construction wood or aluminum profiles on top. Finally, the decking boards are visibly or invisibly fixed to this substructure for the terrace with a fastening system.
Substructure for the terrace with a concrete substructure
Maybe the ground is already concreted. In any case, make sure that the concrete cover is at least 6 cm thick. Now you can place the rubber granulate pads directly on the concrete. Of course, these should be placed where you also put the substructure for the terrace. Again, pay attention to the correct distance.
Finally, the terrace panels are laid again in the desired way. Here you can usually choose between real wood and WPC panels.
Substructure for the flat roof terrace
You should be very careful on roofs. The flat roof and in particular the upper cover must not be damaged. First you should spread out a PE film or a thick weed fleece layer here as well. This will later avoid a chemical reaction with the rubber pads.
Now lay out the rubber granulate pads at the relevant points for the substructure for the terrace. Note that the roof has a specific size. Ideally, you build a stable wooden frame or one made of aluminum that serves as a substructure for the terrace. Screwing the substructure directly to the roof would possibly lead to leaks.
Finally, you can lay your preferred decking again here. In this way, the terrace substructure forms a secure and firm support.
Substructure for the terrace with uneven ground
The ground below the future terrace is not always absolutely level. If possible, you should level the ground here as much as possible. If you want to save yourself the trouble, you should also dig up the subsoil again and cover it with crushed stone and gravel. Differences in height can be compensated for here.
If the subsoil is still uneven, there is the pedestal wooden terrace. As mentioned before, these plates can be adjusted in height using a screw thread. So you can build your terrace even if the ground is uneven.
The rubber pads are placed on the pedestal to prevent slipping. You can then build the substructure for the terrace made of real wood or aluminum on top of this. Then come the terrace panels again.
Terrace substructure – important calculations for a reliable result
With a substructure for the terrace, it always depends on the respective size. If you want to build your terrace yourself, you also have to do some math.
For example, note the correct distances between the individual construction strips. The distances must not be too large, otherwise the decking boards would later sag. This would make the terrace unstable.
The distance between the individual construction battens on wooden floorboards should be around 20 times the thickness of the floorboard. In the case of composite materials, this should be 15 times the thickness of the plank.
The substructure for the terrace must also not be longer than the length of the terrace boards to be used. At best, they can survive a little longer. In this case, these can then be shortened later with a circular saw at the edges.
Terrace substructure – which material do I use for the substructure?
Various materials are suitable as a substructure for the terrace. In the following, we will introduce you to the advantages of the different building materials and which material is best suited for your terrace substructure.
The wooden construction strips
If you are thinking of a real wood terrace, you will find many weather-resistant types of wood here. Here we are talking about a durability class. Larch, thermal ash, Bangkirai or Ipé are often used. If you also want to use this wood as a finish for the decking, then the substructure for the deck should be made of the same material.
It should be noted that the construction wood fortunately does not remain permanently in the moisture due to the support on the stilts. Nevertheless, it is a natural material that can weather over the years.
The aluminum construction strips
If the location of your terrace is often damp and there are also ventilation problems there, then aluminum construction strips are ideally suited for the substructure for the terrace.
Waterlogging in particular cannot harm aluminum. The material itself is quite light and yet torsion-resistant. A terrace substructure aluminum is almost insensitive to weather influences. Therefore, it is also much more durable than wood.
It doesn't look quite as nice, but you won't see anything of this substructure afterwards. You will later cover this with your beautiful decking boards. Aluminum construction strips are usually also used on roofs for roof terraces.
WPC panels are being used more and more frequently today. You can also use this as a substructure for the terrace. The hollow beams are made from a mixture of plastic and wood. The material is weatherproof and dimensionally stable. In addition, it is available in many different colors, which gives you all options for the terrace substructure.
A substructure made of WPC can be chosen in the same color as the upper decking made of WPC. It should be noted that this type of substructure is only suitable for absolutely level surfaces. Otherwise the hard material could break under load.
If you are not sure, you should rather rely on wooden or aluminum construction strips. The upper covering with WPC planks is then also possible.
Substructure for the terrace - pedestals for many bumps
We have come across the term pedestal several times. Admittedly, these little screw-threaded feet are a not-so-cheap alternative. In many cases, however, pedestals make the construction much easier.
As previously mentioned, adjustable pedestals primarily serve to support the substructure for the terrace. The upper plates can be screwed in and out individually in terms of height. This means that you can also compensate for differences in height.
If you want to equalize the heights over a longer distance, you should first place a pedestal at the beginning and at the end and place a construction bar on top of it. You can then place the other pedestals in between and bring them to the right height. It is best to place a spirit level on your construction bar. Then you can see if you are in balance.
As mentioned before, you can also compensate for many unevennesses in the ground with pedestals. Irrespective of this, we recommend that you level the ground as much as possible beforehand and thus level it.