Terrace construction
Updated: 2021-10-11

During the building of the house, an outdoor terrace is installed at the very end of the construction. As one well-off acquaintance put it, there is not even anyone to borrow from. Therefore, the terrace is usually made of cheaper wooden boards and then full of regrets. You must scrub it every year and then apply chemicals. You don’t even want to go out on such an outdoor terrace.

Is it possible to build a terrace that lasts forever? After all, terrace materials and fasteners are exposed to the most extreme conditions. Rain and snowmelt water, high temperatures, UV, double temperatures and UV rays reflected from the glass of the display wall.

It didn’t seem that big of a deal, even though I was in no rush to build a terrace until I found a solution. It turns out that it is possible to build an almost forever-lasting terrace using aluminium profiles for the foundation and WPC terrace boards.  But there are a few catches.



WPC boards for terraces

Many people have already seen WPC boards. But for many, they were not the best. There are quite a lot of cases where WPC boards crack, especially in the vicinity of shop windows. In these areas, the sun's effect is increased, as the terrace boards are additionally heated by the sun's rays reflected off the glass. The cracking is caused by using cheap and low-quality WPC terrace boards.

Wood composite, or WPC, cannot be cheap. It was developed to replace wood from exotic countries, not because of its price but because of its properties. The technology is quite sophisticated: mixing wood dust, plastics as well as binding and colouring materials to produce a new quality. Manufacturers of low-cost WPC use recycled plastic and wood raw materials. Often, residues from the furniture industry with "additives". The use of secondary raw materials will not yield the same results. One board seems to be according to technology, the other is already according to another "technology".


The photo shows weather-resistant boards acquired from "2M Baltic UAB."

Serious manufacturers of WPC decking boards go beyond a few colours and textures. It is possible to order classic boards with grooves that reduce slipping. There are also smooth-surfaced boards that use special technology to minimise slipping. They are just considerably more expensive. There are also boards made of imitation wood which can be used with clinker facades.


Classic terrace boards with surface grooves on the edges. Hollow terrace boards are cheaper, but also have a shorter service life. Hollow boards made from recycled materials are particularly cheap. When purchased from “2M Baltic”, both hollow WPC boards will last for decades.

WPC boards are easy to maintain. Just rinse with a high-pressure stream. Scratches will not be visible as the material of the WPC boards is homogeneous, with a consistent colour throughout its entire thickness.

You can’t even compare it to wooden boards, which need constant cleaning, impregnating and oiling. It is impossible to talk about the naturalness or environmental friendliness of wood when so many chemicals are used.


Installation of an outdoor terrace

An outdoor terrace is most conveniently installed on piles. Even a quite large terrace can be set up in a few weekends. One weekend will be needed to put up the piles and concrete them. The next is for the framing and the installation of the planks.


The piles should be placed at a depth of about 80 centimetres and placed on firm ground. It is most convenient to dig the pits with a soil drill. The drilling shall be carried out at a slightly shallower depth by removing the soil.


To protect it from grass, we cover the bottom of the terrace with agro textile.


The installation of the terrace will be greatly increased if the lower profile is levelled right away. The surface of the terrace should have a slight outward slope to allow water to drain away. Levelling is greatly aided by gravel, which will later be used to cover the agro textile.


In the lower profile, we attach the stake right away. It is preferable to use stainless steel rods for the stake, concreted at least 15 centimetres.

The diameter of the stake depends on its height. For a gap from the pile to the upper section of up to 6 centimetres, the diameter of the pole is 10 mm, for a height of 6-12 centimetres it is 12 mm, for a height of up to 25 centimetres it is 14 mm. The peg is oscillated during insertion to ensure good adhesion to the concrete.


The concrete can be conveniently poured using a funnel. When pouring, a long bar is vibrated to allow the concrete to settle.


The second level of framing is necessary, especially with smaller diameter profiles.

A reliable, well-supported and stable structure should be installed. Loads are balanced across the poles. I used 5x3 cm aluminium profiles. They are connected with self-drilling screws at the corners. Aluminium is suitable both for its corrosion resistance and for its softness and ease of drilling.

The profiles are placed at the edge, with the other profile placed 20 centimetres away. Inside, the profiles are placed every 40 millimetres. The distance may increase if thicker terrace planks are used. In this case, 22 mm for hollow WPC boards.


Terrace planks are attached with special fixings.

The fasteners for the terrace boards should be made of good metal, as these elements lift the terrace board slightly. This creates a ventilated gap where water does not accumulate and the terrace boards will ventilate and last longer. Start with special edge fixings.


How to choose a terrace location

The location of the terrace is selected individually according to the existing conditions. Depending on the vegetation, terrain and proximity to the forest. If there is a lot of greenery or if the house is in a forest and the sun hides behind the trees early, it is better to choose the west side. The east and south sides will be gloomy. For larger spaces, on a hill, where the forest is further away, the east and south sides are best. The wall will provide protection against prevailing northerly winds. The sun setting in the west will not be in sight. Moreover, if there is a pine forest, the sun will give a long reddish glow to the trunks, which is more beautiful than a sunset. In a forest, the reddish sunset is usually not even visible.

Provide an electrical outlet for the equipment on the terrace. Make sure you have lighting installed as soon as possible.

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