INSTRUCTIONS FOR INSTALLERS
PREFACE
This manual provides general construction guidelines and instructions for the installation of skimmer pools to be built using lost polystyrene formwork blocks, completed on-site by laying reinforcement bars and subsequently pouring concrete.
The structures must comply with the following dimensional limits:
- maximum vertical wall height from the bottom: 1.52 m;
- maximum liquid head height: 1.45 m;
and the following constraints related to the geographical location of the structures:
- low seismicity areas: locations in zone 4 or zone 3
- foundation soil with medium or good geotechnical characteristics (allowable pressure not less than 0.9 kg/cm2)
This document does not refer to any specific site, nor to the parameters and geotechnical characteristics of a precise foundation soil; therefore, the verification of compliance with the aforementioned limits and constraints remains the sole and exclusive responsibility of the client or their design engineer and/or appointed works manager.
Failure to comply with even one of these limits and constraints renders the indications and prescriptions, however general, contained herein ineffective, and relieves the author of this document of all responsibility.
REGULATIONS
The following indications and prescriptions are provided in compliance with current regulations, specifically:
- Ministerial Decree of Infrastructure January 17, 2018 and annexed "Technical standards for construction".
- Circular of the Ministry of Infrastructure and Transport January 21, 2019, no. 7 - Instructions for the application of the update to the "Technical standards for construction" as per Ministerial Decree January 17, 2018.
MATERIAL REQUIREMENTS
For the execution of the works in question, the following material resistance classes are required:
a) STRUCTURAL CONCRETE FOR FOUNDATION AND ELEVATION
- Minimum characteristic strength: R’ck = 300 daN/cmq
b) STEEL FOR REINFORCED CONCRETE
- Class B450C, or equivalent class for electro-welded mesh
INDICATIVE QUANTITIES OF REINFORCEMENT BARS
As an indication, the methods for calculating the quantities of reinforcement bars required for a rectangular pool with an internal beach area and a wall height of 1.52 m are outlined.
Calculation parameters:
- Base area (sqm): internal pool area + 50 cm for each side (e.g., 4x8 pool = 5x9 excavation);
- Internal pool perimeter (m): perimeter of vertical walls in contact with water;
- External pool perimeter (m): perimeter of vertical walls in contact with the ground.
In the case of a pool with an external beach area, the protruding dimensions of the beach area itself must also be included in these parameters.
1) Foundation slab: D.8/20”x20” electro-welded mesh; quantity m2: slab area x 2 + 20% (mesh overlap of at least 2 squares)
2) Walls: horizontal D.10 bars, 6.00 m long; no. = internal pool perimeter x 2
3) Vertical bars pos.1 D.12 L=1.60 m; no. = internal pool perimeter x 8
4) Horizontal corner bars pos.3: D.10 L=2.00 m; no. = no. of corners x 10
5) Pavement connection stirrups pos.2: D.8 L=1.00 m; no. = external pool perimeter x 4
All as represented indicatively in the following construction details:
ATTENTION: during execution, any variation to this sizing must refer to the actual values of the design characteristics and parameters, evaluated by the professional based on the real operating conditions.
The following indicative table summarizes the horizontal and vertical reinforcement required for the construction of pools using the EASYBLOK lost insulated formwork system, based on the seismic acceleration at the construction site.
1 - Laying Out
The first step in building a pool is choosing the right location. An area without plants or obstructions, and without manholes or foundations, should be selected.
It is necessary to find a reference square, which could be the house or the garden fence. Based on that, mark the excavation dimensions on the ground.
For example, for a pool with a water surface of 4.00 x 8.00 m, we will have an overall dimension of 4.50 x 8.50 m (the formwork depth is 25 cm), so we will excavate 5.00 x 9.00 m (leaving an additional 25 cm to facilitate work and the necessary space for any recirculation pipes).
For a pool with a water surface of 5.00 x 9.00 m, we will excavate 6.00 x 10.00 m and so on…
Precise calculations will save money on excavation and slab work, and there will be less backfill and fewer settlements.
Therefore, once the area and precise dimensions are chosen, start marking out the pool on the ground.
What you need:
- pointed wooden stakes or rebar;
- a rope;
- white powder (lime, chalk, or cement);
- measuring tape;
- chalk line.
Once the four outermost stakes are fixed, stretch the rope and effectively mark out the pool excavation, distributing the white powder along the string.
Then remove the string and move the stakes outside the excavation to quickly transfer the pool measurements once the excavation is complete.
At this point, all that remains is to re-measure all sides and diagonals, which must be equal, to verify the correctness of the dimensions and squareness of the traced shape.
N.B.: If present, at this stage, it is also advisable to choose where to position the plant room.
A distance of 3 to 5 meters is recommended, and the excavation should be about 10 cm deeper than the room itself. Then, mark out the footprint for the plant room excavation.
2 - Excavation
After marking out, proceed with excavation using an excavator.
ATTENTION: the excavation must be at least 20/25 cm deeper than the planned depth for the pool, in anticipation of the construction of a foundation slab 20/25 cm thick (depending on soil characteristics) reinforced with double D.8/20”x20” mesh resting on spacers of appropriate height.
Therefore, if our pool is to be 1.50m high, we will excavate to a total height of about 1.70 / 1.75m. A few more cm should also be considered for the support feet of the formwork (about 2 cm), for the lining profile (about 1.5 cm) and for the paving (1 or 2 cm thick) but, deliberately, we recommend that the pool be a few cm higher than the ground level, so that rainwater drains towards the surrounding ground and not into the pool itself.
Always consider the highest point near the pool as the zero point.
NB: At this stage, if present, install the main drain at the correct level.
3 – Area preparation and slab pouring
Once the excavation is complete, we will re-mark the pool inside it. This process is very quick, thanks to the previously placed stakes. At this point, you can proceed with laying the double layer of electro-welded mesh. This operation should be done by lifting the mesh plane off the ground with spacers, so that the mesh is raised at least 5 cm from the ground.
Then, proceed by laying the second layer of mesh on top of the first, maintaining the spacing between the two layers. Numerous spacers will be needed to ensure excellent stability during pouring. The meshes of the same layer should overlap by at least 40 cm to create stability. It is also advisable to have reference points between the meshes to which the concrete plane will be aligned. Therefore, insert metal stakes on which the reference levels will be struck, in order to achieve a perfect plane. Once the foundation reinforcement operations are complete, use the concrete pump for pouring.
ATTENTION: ensure that the metal stakes of the base are perfectly leveled, so that the elevations are under control at all times.
Then proceed with pouring the slab. It is recommended to use concrete with good consistency (S3-S4 class), to facilitate operations and distribution.
During pouring operations, prioritize the outer part of the slab, where the pool walls will be placed, then proceed with the inner part.
It is recommended to use a screed for leveling the slab and subsequently a power trowel for quartz finishing.
It is very important that the bottom is perfectly leveled and smooth. Any small imperfection will be highlighted by the PVC lining, and the water will emphasize every defect like a magnifying glass.
4 – Installation of Easyblok formwork and concrete pouring
Allow sufficient time for the slab to dry completely.
Using a tape measure, identify the 4 internal vertices of the pool perimeter and mark them with nails. Subsequently, anchor a chalk line to these nails to redefine the pool's shape. It is advisable to verify the actual squareness of the defined shape by measuring the diagonals and sides. The diagonals must be identical to each other, as must the long and short sides.
Now begin installing the EASYBLOK formwork blocks clockwise or counter-clockwise, with the feet facing downwards, interlocking them.
Once the first course is completed and the structure is square, we can prepare the vertical reinforcement by drilling holes (∅16, 10/11 cm deep, 25 cm apart, in a zigzag pattern) in the base with a drill.
The vertical rebar will then be positioned before laying the last course of formwork.
The vertical D.12 bars should then be inserted into clean ∅16 holes, 100-110 mm deep, filled with fine-grained cementitious mortar, Basf Masterflow 960 one-component, or two-component chemical adhesive. Alternatively, rebar can be inserted into ∅12 holes, 100-110 mm deep, with simple mechanical compression.
In the formwork block positioned at the corner, cut a side window in the upper part with a saw, to create a continuous opening for laying the reinforcement and subsequent concrete pouring.
The various courses of formwork blocks, to be connected to each other, must be staggered by at least 50 cm (2 modules), exactly as you would with Lego.
The formwork blocks are arranged in 1.25 m lengths, each block consisting of 5 separable 25 cm modules, thus ensuring they interlock perfectly and allowing for the desired overall length.
The openings at the ends must be closed using the appropriate sealing keys. Two for each formwork block, positioned at an angle, to prevent concrete leakage during pouring.
Then position the double horizontal reinforcement bars inside each course of formwork. Ensure that the courses of horizontal bars overlap by at least 50 cm. At the perimeter corners, the horizontal bars must be appropriately bent at 90 degrees and continue along the next side to ensure maximum robustness.
N.B.: Avoid overlapping horizontal rebar in the same spots repeatedly.
Once the horizontal and vertical reinforcement is complete, it is advisable, to secure the pool and the surrounding paving, to position the external screed anchor points:
Once the formwork is laid, you can proceed with the installation of the built-in parts: skimmers, jets, lights, filter wall (if present), etc.
Also prepare the support for the level control (if present).
Position the accessories at the desired point and mark their footprint with a marker, then cut the affected formwork blocks following the trace. Once the positioning phase is complete, if you are sure you no longer want to move the special parts, you can proceed to fix them with polyurethane foam, which, drying and solidifying on contact with air, fixes the part almost immediately.
Do not overdo it with polyurethane foam; the flow of concrete must be guaranteed.
Position the Zavatti patented profile, interlocking, before pouring the walls. The Zavatti profile will be the zero point (starting point) for the reinforced PVC lining and the zero point (support point) for the external paving of the pool.
Before proceeding with concrete pouring, double-check that the structure is level and square.
With high-density EASYBLOK formwork, there will be no need to reinforce the structure either before or after pouring, thus saving time and money.
Then we will see in detail, based on the chosen filtration system, how to proceed with its installation.
In the meantime, let's finish explaining the concrete pouring phase.
The concrete used (cement, sand and fine gravel) must have a consistency that is neither too liquid, to avoid excessive pressure inside the formwork, nor too dense, to avoid the formation of aggregate clumps that prevent the correct propagation of the concrete inside the EASYBLOK formwork.
Therefore, fine-grained concrete is recommended with a consistency class slump S 4> 160 mm and a maximum aggregate size between 10 and 12 mm (maximum aggregate diameter 20 mm), taking care to compact it well.
During pouring with mechanical means, such as concrete pumps, etc., it is advisable to distribute the pouring load along the perimeter without remaining at the same point, so as to evenly distribute the thrust.
Furthermore, as indicated in the figure, the correct pouring direction consists of letting the concrete fall directly onto the formwork reinforcement and not directly into the cavity.
With EASYBLOK, pouring can be done in a maximum of two passes.
It is not necessary to vibrate the concrete pour as the vibrator itself could damage the integrity of the EPS formwork. Adjacent to the installed accessories, in order to allow the concrete to flow correctly, manual operations must be carried out with the aid of a tool (e.g. an iron rod) to ensure that the pour remains completely in contact with the accessory itself.
At the end of the process, level the surface with a trowel and clean the construction site. Then check that the top of the perimeter is perfectly level using a spirit level. Once the structure has been poured, wait a minimum of 10 days for the concrete to cure before proceeding with the work.
With EASYBLOK, pouring can be done in a maximum of two passes.
It is not necessary to vibrate the concrete pour, as the vibrator itself could damage the integrity of the EPS formwork. Adjacent to the installed accessories, to ensure proper concrete flow, manual operations must be performed using a tool (e.g., a rebar) to ensure that the pour remains completely in contact with the accessory itself.
At the end of the process, level the poured channel with a trowel and clean the construction site.
Then check that the top of the perimeter is perfectly level using a spirit level. Once the structure is poured, wait at least one day before continuing with the work.
As soon as the structure's concrete pour is dry (even from the next day), you can proceed with manually pouring the overflow holes, using fine-grained cement mortar, mixing fine Po sand and 325 cement.
After that, proceed with cutting the patented Zavatti profiles, both internal and external, placing them at the correct height on the corresponding channel formwork. Then check that the top of the perimeter is perfectly level using a spirit level.
Finally, as early as the next day, it will be possible to lay the channel lining membrane, flange the channel bottom inlets, lay the profiles, and install the level control and overflow.
Instructions and advice for the company in charge of external works
Once the pool walls have been poured, wait a minimum of 10 days for the cement to cure before proceeding with external works such as drainage, drains and hydraulic and electrical connections, backfilling with gravel, and pouring the floor slab.
5 – LEVEL CONTROL AND OVERFLOW
Prepare the pit for level control and overflow near the pool.
The pit should measure 30x60 cm.
PLEASE NOTE: IF THE PRESSURE IS HIGHER THAN 1.5 BAR, USE A PRESSURE REDUCER AT THE WATER INLET (USING THE APPROPRIATE REDUCERS) TO PREVENT THE LEVEL CONTROL FLOAT FROM BURSTING.
6 - Biological dechlorinator (necessary for sand filter systems)
Position the biological dechlorinator pit (with the pit for the submersible pump power supply alongside it) approximately 1 meter from the pool's technical room and make all hydraulic and electrical connections.
7 - Backfilling with fine aggregate
As soon as all pits, drains, outlets, and hydraulic and electrical pipes have been correctly positioned, proceed with backfilling using fine aggregate (gravel, sand, or recycled material).
8 - Pool light connections
Before pouring the slab, make the electrical connections for the pool lights.
9 - Floor slab pouring
After that, you can proceed with pouring the reinforced concrete slab for the paving (approximate height 15 cm), taking into account a 1% slope per meter towards the pool. Therefore, considering the 0 level corresponding to the water level, keep at least 30 cm for backfill (which will be aggregate/sand/gravel/recycled material); 15 cm for the reinforced slab, and finally about 3 cm for adhesive and flooring.
N.B. In the presence of visible pipes or fittings (not poured) outside the pool wall, cover them with sand.
Wait for the slab to be perfectly dry and complete the paving by laying the chosen tiles and landscaping the garden.
10 – Installation of reinforced lining membrane and finishes
The last thing to do now is to internally line the pool with the reinforced PVC lining membrane. The membrane supplied in the kit comes in rolls and will need to be heat-welded on site using the appropriate heat guns.
Thanks to the perfection of the EASYBLOK formwork, wall rendering can be avoided; simply install the self-adhesive polyurethane PVC mat on the walls.
For internal steps and stairs, plasticized angles are provided to ensure a professional heat-welding installation.
Once the lining is installed, proceed to flange all accessories in the pool.
11 – INSTALLATION OF OVERFLOW CHANNEL TILES AND POOL START-UP
Once the liner installation is complete, you can immediately proceed with filling the pool, preferably with tap water.
Wait for the water to reach the overflow level and for the surrounding channel to fill correctly, then switch on the filtration system and proceed with water treatment using chemical products.
Then lay the necessary spacers to support the tiles covering the overflow channel and complete by laying the tiles themselves.
It is possible to customize the pool with a ladder or a beach:
The LADDER is a pre-assembled block, easy and quick to install.
Supplied with plasticized angles for a professional liner installation. Includes a coil of non-slip safety reinforced PVC liner.
The BEACH, on the other hand, needs to be assembled on site.
Supplied with plasticized angles for a professional liner installation. Includes a coil of non-slip safety reinforced PVC liner.
Suitable for creating a beach with a maximum size of 10sqm.
