How to install EPS V-foundation boxes: step by step

Step 1 – Position the elements

1.1 Start with a level sand blinding layer with a minimum diameter of 50 mm.
Note the base thickness of the EPS U-foundation box:

• 7 cm at 100 kPa
• 6 cm at 200 and 300 kPa

Maximum deviation in the groundwork: 1 cm.

1.2  Set out a string line for the dimensions and place the formwork tightly along the line.
Allow for a wall diameter of 100 mm. We recommend using the external dimension of the foundation as your reference. (See figure V.01)

1.3 Fit the sawn corner pieces as tightly together as possible. Secure them with 2 pegs per corner. (See figure V.02)



1.4 Cut recesses for the piles directly as you install them. Leave a maximum of 2 cm of space around the pile heads.

1.5 When cutting the boxes to size, keep at least one tongue or groove edge intact. This keeps the connection strong and ensures everything fits properly.

Step 2 – Install the reinforcement

2.1 Place concrete spacers on the base of the foundation box.

2.2 Carefully lower the reinforcement cage into the foundation box. (See figure V.03)

2.3 Fit plastic flat base spacers to the side of the cage.

2.4 Check that the spacers are correctly positioned against the formwork wall and that the cage is properly supported on the concrete spacers.

Step 3 – Cut openings for service penetrations

3.1 Cut the openings for service penetrations to size using a handsaw or jigsaw. (See figure V.04)

3.2 Keep the clearance around the opening as small as possible. Maximum 2 cm.

3.3 Place the sleeve/duct through the opening.

3.4 Seal the opening around the penetration with PU foam. (See figure V.05)

Step 4 – Securing the formwork

4.1 Backfill the ground around both sides of the formwork. This prevents movement during the pour. On the inside, allow space for the floor insulation: fill up to the top of the formwork, minus the thickness of the floor insulation.

4.2 Secure the corner pieces firmly with corner tie-wraps, 4 per corner. (See figure V.06)

Step 5 – Install the floor insulation

5.1 Fit the floor insulation tight to the inside of the formwork. Note: the boards sit on the sand bed, not on the formwork itself.

5.2 Lay a sheet of foil over the floor insulation.

5.3 Place spacers on top of the foil.

5.4 Lay the slab reinforcement on top of the spacers.

Step 6 – Seal joints before pouring

Prevent leakage. Seal all openings with PU foam in the following places:

• Sawn ends on foundation boxes cut to size
• Around service penetrations in the formwork wall
• Unexpected gaps in the formwork

(See figure V.08)

At Betonstaal.nl you can order V-foundation boxes with delivery within 4 working days, starting from just 1 piece. Combine it with your reinforcing mesh and rebar for a complete foundation in a single order. View the EPS V-foundation formwork range and and add them straight to your shopping basket.