Building a BPC and WPC terrace on a slope – My new pool terrace with recycled boards
BPC decking, slope, pool construction and substructure – in this post I show how I built my new pool deck with recycled BPC boards, solid larch beams and aluminum profiles. The pool is located on a slope, which places special demands on stability, gradient and load-bearing capacity. I share my experiences with BPC and WPC, explain the differences in installation and show what really matters when it comes to a durable, resilient decking construction. If you want to build a patio yourself, you’ll find lots of practical tips and insights here.
What you can expect in this blog post:
- Review of my first BPC terrace around the old steel wall pool
- Reasons for dismantling and switching to a formwork pool
- Planning and construction of the new pool terrace on a slope
- Construction of a stable substructure made of larch wood and aluminum profiles
- Laying the BPC decking boards with invisible fastening system
- Advantages and disadvantages of WPC and BPC in direct comparison
- Reusing old floorboards and materials – sustainable & well thought out
- Solution for the flush skimmer cover and invisible access
- Outlook for the planned LED patio lighting
Looking back: My first BPC terrace around the steel wall pool
Before I built my new pool from formwork stones, there was a sunken steel wall pool in the same place. At that time, I decided to build a free-standing wooden substructure around the pool, onto which I laid BPC boards. This was my first major decking project with this composite material made of wood fibers and plastic, and the installation worked well – at least for the first few years.
In my previous blog post on building the free-standing substructure for the BPC planks, I show in detail how I prepared the foundation, set the post supports and attached the planks to a stable wooden substructure. The construction was technically well thought out – however, over time I noticed that the BPC boards began to buckle slightly due to strong sunlight. Moisture and pests also affect the construction in the long term.
As our desire for a larger, more durable pool project grew, we finally decided to dismantle the steel wall pool – along with the entire terrace. In my article “Converting the pool: Dismantling the pool & decking made from BPC boards”, I documented the dismantling process in detail: From removing the planks to dismantling the pool and removing the old pool technology.
The new pool was then constructed from concrete formwork blocks. I also took the opportunity to professionally lay the pool edge stones and prepare the base for the new pool terrace at the same time. I also accompanied this construction phase in the blog – in my article “Laying pool edging stones and building a pool terrace yourself” you can find all the details on preparing the edges and connecting the new BPC terrace to the pool with a perfect fit.
Video: Dismantling my old BPC pool terrace – what it used to look like
Before our current stone pool with new terrace could be built, I first had to dismantle our old steel wall pool and BPC terrace a few years ago. In this video you can see the condition at the time and the complete dismantling of the old WPC/BPC pool deck with wooden substructure.
This video offers an exciting look back at the beginnings – and serves as a thought-provoking introduction to the current project:
the construction of my new pool deck with recycled BPC boards, stable aluminum-wood substructure and perfect connection to the pool edge stones.
The pool itself has already been completely rebuilt after demolition – now it’s the pool terrace’s turn. If you want to see how the grounds and the terrace have changed in recent years, be sure to take a look!
In my playlist for the project pool you can watch the whole process in peace.
I have recorded the dismantling of the WPC/ BPC pool terrace in the video Pool rebuild – dismantling pool terrace | BPC planks | substructure | pool technology.
If you want to see more of me and my projects, feel free to check out my YouTube channel.
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Price: € 32.25instead of: € 34.20
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Price: € 5.95instead of: € 11.74
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Price: € 242.19instead of: € 377.00
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Why I chose BPC and recycled materials
When planning my new pool terrace, it was important to me to reuse as many existing materials as possible. My old BPC boards, which I had already used for a previous decking project, were to be installed again – despite the fact that some of them had warped slightly under strong sunlight. The main reasons for my decision were the high resistance to moisture, good durability, easy cleaning with water and the pleasant appearance of the planks.
WPC and BPC in comparison: properties, advantages and disadvantages
WPC (Wood Plastic Composite) and BPC (Bamboo Plastic Composite) are both composite materials that are ideal for outdoor use – whether on the patio, by the pool or in the conservatory. While WPC is based on a mix of wood fibers and plastic, BPC uses bamboo flour instead of wood. Both variants are considered easy to care for and durable, but differ in some details:
Advantages of WPC:
- Low water absorption, therefore well suited for permanently damp environments
- Homogeneous surface, often embossed with wood texture
- Easy to clean, splinter-free and non-slip
- Large selection of colors
- Well suited for terraces and conservatories
Disadvantages of WPC:
- Higher temperature expansion in strong sunlight
- Can heat up more in dark shades
- Slight fading may occur under high UV exposure
Advantages of BPC:
- Higher dimensional stability due to dense bamboo fibers
- More natural look with high-quality finish
- Robust against temperature fluctuations
- Very suitable for use by the pool and in the garden area
Disadvantages of BPC:
- Slightly more expensive to purchase than simple WPC
- Slightly more sensitive to waterlogging if the underside is poorly ventilated
In my case, I deliberately chose BPC boards because they have proven to be resistant to moisture and temperature-stable when laid well and with sufficient distance from the ventilation. The application area directly by the pool places high demands on the material – BPC has proven to be a suitable solution here.
My previous experience with WPC and BPC in the garden
I gained my first experience with WPC floorboards back in 2012. In my previous article “Installing the WPC decking boards”, I document the construction of my patio with classic WPC boards. At that time, it was noticeable that the planks became very hot due to the sunlight and bent quickly if the substructure was inadequate. Mounting with clips was also not always reliable, especially with higher tensions due to material expansion.
Five years later, I started the project “Building the substructure and laying the BPC boards”. Here I decided to use BPC for the first time, in combination with a more stable substructure. The BPC decking boards impressed me with their better dimensional stability, their pleasant natural look and the ease of installation. However, long-term testing showed that excessive spacing in the substructure led to some planks buckling slightly in high heat.
This experience flowed directly into my current project: The substructure was deliberately built narrower and more stable. This allowed me to compensate for the known weaknesses and make the most of the advantages of the material.
- HOCHWERTIGES MATERIAL – Recycelbar, besonders formstabil & robust dank rutschfestem WPC-Verbundstoff (aus ca. 60% Holz & 40% Kunststoff) - 1. Wahl
- SPLITTERFREI - Barfußfreundlich & rissfrei sorgt der hohe Kunststoffanteil der Terrassen-Platten zusätzlich für Resistenz gegen Pilz- & Insektenbefall
- BESONDERE QUALITÄT - Frei von toxischen Mitteln sind die Garten-Balken des Terrassenbodens besonders leicht zu reinigen & bis -30°C frostsicher
- WETTERFEST - Unser Balkon Kombi-Set Bodenbelag ist weitaus UV-beständiger als Holz, da er Feuchtigkeit abstoßen & hohe Temperaturen ausgleichen kann
- LIEFERUMFANG – Komplett-Bausatz Basic Line mit 4 Hohlkammern (wahlweise in Hellgrau, Dunkelgrau oder Mocca Braun) inklusive Unterkonstruktion + Clips + Schrauben + Bohrer + Bits
Pool terrace – build your own substructure on a slope
Building my BPC pool terrace on the south side of the pool presented me with a very special challenge: the slope of the property. While the pool on the north side is embedded almost at ground level in the terrain, it protrudes around 1.50 m out of the ground on the south side due to the terrain. This is exactly where the new pool terrace was to be built – an area that had to be visually appealing, but above all stable and safe to walk on.
The challenge of a slope: load-bearing capacity, alignment and access
The terrain offset of around 1.50 m posed several challenges:
- The entire terrace surface had to be raised so that it was flush with the edge of the pool.
- A solid substructure was needed to reliably bear the weight – especially in the free-standing area on the slope.
- At the same time, the construction should remain easily accessible, for example for maintenance of the skimmer or the LED spotlight.
I decided to reuse the existing larch beams and BPC boards from the old project as much as possible. This sustainable solution required precise planning, particularly with regard to the slope, spacing of the counter battens and bolting to point foundations.
Building the substructure from wood and aluminum profiles
Load-bearing substructure with wood and metal
The substructure of the pool terrace consists of solid beams made from local larch, which I already used for my first pool terrace – and for good reason. Larch wood is naturally weatherproof, resistant to moisture and pests and has a high mechanical strength.
In contrast to untreated spruce or pine wood, larch can be used outdoors without any problems – even without chemical impregnation. The high resin content also makes it resistant to fungi and insects.
However, larch also has a few disadvantages: The wood tends to crack over time if it is exposed to strong sunlight and dryness. It also performs slightly better than hardwoods when exposed to fluctuations in temperature and humidity. Nevertheless, the advantages outweigh the disadvantages for me – above all because I can source the wood regionally and it is easy to process.
95×95 mm thick larch beams were used for the load-bearing elements. I attached these to the wall with solid wood screws, matching post shoes and heavy-duty brackets and screwed them together. The construction is therefore not only stable, but also permanently resilient.
One major advantage of this project was that I was able to continue using the existing point foundations from the previous terrace construction. I made these myself at the time by first digging round holes with a spade and inserting 140 mm KG pipes vertically into them. I then filled the pipes with concrete to create a stable, frost-resistant point foundation with a clearly defined height and shape.
This construction method has already proved its worth for me several times – including when I built my WPC terrace with garden kitchen on a slope, where I had similar conditions.
This method is particularly suitable for free-standing structures such as terraces, walkways, raised beds or even small garden sheds where reliable load distribution is required without a continuous foundation slab. I had already worked with similar solutions in my early project to create the first garden terrace – and over the years I have gained important experience that I was able to incorporate into the current project.
Video about the project: Building a BPC pool terrace on a slope
In my YouTube video, I show the complete construction of the BPC decking on the slope, documented step by step – from setting the substructure and laying the boards to the finished pool surround. I not only explain my approach, but also share many practical tips and experiences from previous projects. The video offers an ideal visual insight into the implementation on site.
The video is part of my project series “Project Pool“. You can find more videos on dismantling our steel wall pool and building our new formwork pool in the garden in the Pool category.
If you want to see more of me and my projects, feel free to check out my YouTube channel.
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Laying the planks on aluminum profiles – Laying BPC correctly
Laying BPC planks with a system
This time I screwed 50×20 mm aluminum profiles onto the load-bearing larch beams. These profiles are particularly resistant to moisture, corrosion-free and provide an optimum support surface for the floorboards. Their dimensional stability and durability in particular make them ideal for use as counter battens under BPC or WPC boards.
Each drill hole was precisely pre-drilled with a high-quality cobalt drill. This was necessary because I quickly realized that direct screwing in is not possible with aluminium profiles. The screws for fastening the aluminum profiles to the wooden beams and the screws for the connecting clips either broke off or immediately became blunt. Nothing worked here without pre-drilling – that is one of the few disadvantages of this construction method. The big advantage, however: The aluminum profiles provide permanent support, do not warp and ensure an even distribution of the loads on the substructure.
The planks were laid across the edge of the pool and flush with the pool edge stones. The decisive factor for me was the correct spacing of the aluminum profiles to prevent them from bending later – an experience I had already had with my first BPC pool terrace.
My experience with WPC and BPC substructures
On my original BPC decking around the old steel wall pool, I had used counter battens made from WPC profiles. At the time, this sounded like a modern, low-maintenance solution – in practice, however, the WPC profiles proved to be less than convincing. They became brittle over time, deformed significantly, and although I had laid the profiles in a tight grid of 40 cm, the boards still deflected. The load distribution was good, but the dimensional stability of the WPC counter battens was simply inadequate.
Later, I used 50×70 mm larch wood as counter battens for my large WPC terrace with garden kitchen, which was built as a raised terrace over KG pipes. This solution lasted for over 10 years – until I replaced it with new larch beams and aluminum profiles last year as part of the patio renovation. I realized once again that wood weathers over the years – even larch.
When removing the old boards, I noticed that many of the screws for the decking clips were only 1 to 1.5 cm deep in the wood and had already pulled out in some places due to the ageing of the wood. This realization was a clear reason for me to use aluminum counter battens this time – to significantly increase the long-term stability and extend the service life of the entire terrace.
You can find the complete renovation of this WPC terrace and my conclusion on the switch from wood to WPC and aluminum profiles in the article “Renovating the garden terrace – the switch from wood to WPC and aluminum profiles”
- Material: Stahl, feuerverzinkt
- Abmessungen: Gesamthöhe 150 mm - Tiefe 60 mm - lichte Breite 91 mm - Einstandshöhe 100 mm - Materialstärke 4 mm - Anzahl Löcher 8 / 1 - Loch-Ø 11 / 14 mm
- Ausführung: zum Aufschrauben
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- Alberts bietet nicht nur ein umfangreiches Sortiment an hochwertigen Pfostenträgern an. Wir führen auch eine Vielzahl von Profilen - Blechen und Winkeln - attraktive und sichere Fenstergitter sowie praktische und dekorative Zäune.
Laying floorboards with concealed fastening system – precise and recycled
I reused the invisible fastening system from my old decking to lay the BPC boards – another point where I paid attention to sustainability and resource conservation. The clips or brackets of this system engage in the side grooves of the BPC boards and ensure a concealed screw connection with no screw heads visible on the surface.
First, I pre-drilled the holes for the clips with a cobalt drill bit to avoid the risk of damaging the material in the aluminum profile. I then placed the clips in the center of the profile and fastened them with a screw – not completely tight, but only lightly tightened at first. This allowed me to slide the next plank with its groove exactly into the clip without the system jamming or warping.
To get the plank precisely and completely into the clip, I used a chopping board and carefully hammered it in as far as it would go. I only drilled the holes for the next clips and fixed them loosely once the new plank was in place. The clips of the previous connection were then finally tightened with my Makita cordless screwdriver, equipped with a ratchet function on level 15.
This procedure has proven to be particularly efficient and gentle on the material – especially with floorboards that have already been used several times, where over-tightening the screws can lead to damage. At the same time, the system ensures a uniform joint pattern, a stable connection and a clean look that underlines the high-quality impression of the terrace.
- ✅ Befestigungsset WPC BPC für die Montage von WPC/BPC Terrassendielen mit seitlicher Nut.
- ✅ Mit den Clips können Sie Ihre BPC- oder WPC-Terrassendielen ohne sichtbare Schrauben verlegen.
- ✅ Lieferumfang: WPC/BPC Clips 50 Stück inkl. Schrauben + Bit.
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Additional work: Skimmer cleverly integrated and made invisible
When building the new pool terrace, I had to integrate the skimmer into the construction. My original plan was to make the opening of the skimmer flush with the patio deck so that the cover would later be flush with the BPC boards. In practice, however, it turned out that the existing collar of the skimmer was too short and did not reach up to the final terrace height.
After my video was published, an interesting tip came from a viewer: a suitable extended skimmer collar could be created using 3D printing. I thought it was a great idea, but the suggestion came too late – and I don’t have a 3D printer myself, nor do I have any experience in designing a model for such an application.
Instead, I opted for an inconspicuous and functional solution: I closed the pool deck above the skimmer and planked it with BPC boards throughout so that the skimmer disappears completely. However, the surface was designed as a removable section so as not to make maintenance more difficult.
Specifically, I laid the aluminum profiles continuously to the left and right of the skimmer, but planned them in such a way that they do not block the middle area. I mounted three additional aluminum profiles above the skimmer itself. These fit exactly between the fixed plank sections and provide sufficient support on the wooden beams to give the structure stability.
I then attached four BPC boards to these profiles to create a removable hatch that blends seamlessly into the deck. When closed, the area is indistinguishable from the rest of the patio, the planks are visually continuous. If I want to access the skimmer, I can simply remove the entire hatch and have full access for cleaning or maintenance.
This solution is functional, durable and fits in perfectly with the rest of the patio design – without any visible technical installations.
- 25 Clips
- inkl. 25 Schrauben (4,8 x 35 mm)
- Farbe schwarz
- Marinestahl
- Terrassendiele Zubehör
Precise cutting of the planks – subsequent and flush to the end
When laying the BPC planks, I deliberately decided not to cut them to the exact length. During installation, the planks were only roughly cut to size with my cross-cut saw, making sure that there was sufficient overhang on both sides – this meant that each plank could be fixed quickly without time-consuming measuring.
Only after all the planks were fully assembled did I cut the final lengths with the circular saw. To do this, I positioned a guide rail exactly on the cutting line and fixed it with screw clamps. This allowed me to cut all the planks to a uniform size in one clean, continuous cut – both on the outer and inner edges of the walkway. The distance between the planks and the pool edge stones is now around 1 cm – ideal for avoiding tension in the event of temperature fluctuations or movement of the material. The width of the bar is around 80 cm in total.
This procedure offers clear advantages over cutting each individual plank to size before installation:
- The planks can initially be installed quickly and without constant measuring
- Small dimensional deviations or offsets in the substructure are not significant at first
- The final cut ensures an absolutely straight alignment across the entire edge of the terrace
- Cutting edges are outside the field of vision and can be executed precisely, cleanly and visually perfect
This procedure is particularly worthwhile for multi-part bar constructions or planks with a textured profile, as it is much more efficient and creates a harmonious overall appearance.
- Lieferumfang Handkreissäge 2 x Akku Ladegerät Makpac
Outlook: Terrace lighting still in the planning stage
Even though the construction of the terrace has been completed, there is still one issue to be addressed: the lighting. I would like to integrate discreet and functional patio lighting in the next few weeks – but I’m still not quite sure which variant would be best.
There are currently two options to choose from:
- LED spotlights that are embedded directly into the BPC boards from below and provide spotlighting.
- LED strip light along the edge of the patio, creating indirect, uniform lighting.
Both systems have their advantages and disadvantages: spots look modern and unobtrusive, but require precisely fitting cut-outs. A strip light is easier to install, but clearly emphasizes the lines of the patio. I’m looking forward to hearing about your experiences – please write me a comment about what worked well for you or what you would recommend.
Conclusion: Sustainable BPC pool terrace with a well thought-out design
With this project, I have created a functional, stable and visually appealing pool terrace that meets the special requirements of the hillside location. By using recycled BPC boards, a combination of larch wood and aluminum profiles, as well as a well thought-out fastening and installation technique, I was able to further develop many experiences from previous projects.
The terrace is not only visually successful, but also technically well thought-out – from the substructure to the skimmer solution. I am particularly pleased that I was able to reuse many materials from previous construction phases – in a sustainable, cost-saving and resource-conserving way.
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- Materialien: S2 legiertem Stahl ;Typ des Kopfes: Torx ; 11 Stück 100mm Torx lang Bits Schraubendreher Set
- Magnetischen Bits, Dank magnetisierung haften die Schrauben auch am Bit und gerade in tieferen Löchern muss man den Gegenstand nicht umdrehen/schütteln damit die Schraube raus kommt, was Ihre Arbeitseffizienz verbessert.
- Art des Schaftes: 6,35 mm/1/4 Zoll Hex, Magnetischen lang Bit In der Installation kann leicht saugen Schrauben, Elektro-Schraubendreher, manuelle Schraubendreher, elektrische Bohrmaschine, Gruppe allgemeine Werkzeuge.
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Summary: Building a pool terrace with BPC boards on a slope
In this article I show the complete construction of my new BPC terrace by the pool, which was realized on the south side on a slope. The focus is on a stable substructure made of larch wood and aluminum profiles, the installation of recycled BPC planks and invisible fastening with clips.
Previously, there was a sunken steel wall pool with an old BPC terrace in the same place, the dismantling of which I documented. The new pool made of formwork stones was edged with pool edge stones, which were precisely taken into account when building the terrace. The point foundations that I had already used for my WPC terrace with garden kitchen were used again – this time supplemented by an optimized load distribution with aluminium profiles.
I share my experiences with BPC and WPC, discuss the advantages and disadvantages of both materials and explain why I opted for a combination of sustainable reuse and technical improvement.
Special detailed solutions such as the removable skimmer cover, the precise fitting of the boards with the help of a beater board and the planned LED patio lighting round off the project.
Conclusion: A well thought-out, durable and weather-resistant pool deck made of BPC boards that is both functional and visually appealing – and is the result of many years of personal experience.
Frequently asked questions about the BPC pool terrace on a slope
1. why were BPC boards used and not WPC boards again?
BPC planks offer greater dimensional stability and robustness against temperature fluctuations. In the pool area, where moisture and UV radiation have a lasting effect, BPC boards proved to be more resistant. In addition, existing floorboards from a previous project could be reused.
2. how was the slope solved when building the terraces?
The height offset of around 1.50 m was solved with a free-standing substructure made of larch beams. The beams rest on existing point foundations and were additionally supplemented with aluminum profiles to create a stable, level terrace surface at the height of the pool edge stones.
3. what materials were used for the substructure?
95×95 mm larch beams were used for the supporting structure. These were bolted to 50×20 mm aluminum profiles, which serve as dimensionally stable counter battens and are also weather-resistant.
4 Why was aluminum preferred as counter-battening?
Aluminum profiles are corrosion-free, do not warp and provide a permanently stable base. Compared to wood or WPC profiles, they have a significantly higher long-term stability – especially in changing weather conditions and in the pool environment.
5. how were the BPC planks fixed?
A concealed fastening system with side-gripping clips was used. The clips were screwed onto the aluminum profiles. All holes were drilled with cobalt drills to facilitate screw guidance in the aluminum and prevent damage.
6. how was the skimmer integrated into the terrace surface?
The skimmer area was realized with a removable plank section. Four BPC planks lie on transverse aluminum profiles, which are loosely laid and easy to remove. The surface is flush with the rest of the terrace, but remains accessible for maintenance and cleaning.
7. which components of the old project could be reused?
In addition to the BPC boards, larch beams and fastening materials from the previous terrace construction were also used again. Reuse saved resources and material costs and was in line with the sustainable focus of the project.
8. what experiences have you had with WPC substructures?
WPC counter battens proved to be less dimensionally stable in long-term use. Deformations, brittleness and weakening screw connections led to an unreliable structure. Based on this experience, the company switched to aluminum profiles.
9. how high-maintenance is a BPC decking?
BPC planks are easy to maintain. Water, a broom and, if necessary, a neutral detergent are sufficient for regular cleaning. High-pressure cleaners should be used at a distance and at low power. Oiling, painting or impregnating is not necessary.
10. is the terrace barefoot-friendly?
BPC planks are splinter-free, slip-resistant and get less hot in the sun than many other materials. The surface remains grippy even when wet. This makes the terrace ideal for walking barefoot – especially around the pool.
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