Step 1: Make sure the frame is straight

We start by fitting the level screws as close as possible to the outer edges of the frame. The level screw ensures that the frame will be straight. Use at least two screws per window. If the window has a centre mullion, place another screw under it as well. When installing doors, more screws are needed at the bottom because the threshold will bear loads – the screws must therefore support it along its entire length.

Step 2: Fit the level screws

If the wall is concrete, pre-drill a 6.0 mm diameter hole about 40 mm deep and use a nylon plug N 6 × 30. Fixing into wood or into a steel profile (max. 2.0 mm thick) with timber reinforcement needs no pre-drilling.

Step 3: Position the frame

Stand the window frame in the opening on the level screws. The air gap under the frame should be approximately 15 mm. To centre the frame accurately, we recommend using two or more Pumpbag inflatable cushions, which you inflate at the sides between the frame and the wall until the frame is centred.

Step 4: Align

Place a spirit level on the frame and adjust the level screws with the adjustment tool until the frame is straight.

Step 5: Fix the frame

Now it is time to fix the frame! Use a TX25 bit.

Fixing the frame into a hard or porous material?
If you are fixing the frame into concrete, lightweight concrete, expanded clay aggregate concrete, brick or hollow brick, you must insert a plug before driving in the frame screw.

Fixing the frame into wood?
When fixing into wood you do not need a plug and can drive the frame screw in directly.

When driving the frame screw through the holes in the frame, make sure that the teeth under the screw head bite into the frame material. The teeth grip the frame and make it possible to adjust it afterwards. For a secure installation, also make sure that the screw reaches at least 45 mm into the load-bearing material of the wall.

Step 6: Fine-tune with the frame screw

If the frame is not straight once all the screws are in, you can easily align it by screwing the frame screw in or out. Thanks to the teeth under the screw head, the frame moves together with the screw as you turn it. Use a spirit level to check both the horizontal and the vertical position.

Step 7: Cover the holes with cover caps

Once all the frame screws are in and the frame is straight and centred, cover the holes in the frame with cover caps. The cover caps come in several colours, so the fixing will be discreet whatever the colour of the window.

Step 8: Insulate the gap

Fill the gap between the wall and the frame with gun foam. We recommend Expand gun foam, with an isocyanate content below 0.1%, which provides good sound damping and thermal insulation. It adheres to most materials, e.g. wood, metal, concrete, stone, foam plastics and extruded polystyrene.

Isocyanates – mandatory training!

Because working with isocyanates carries a risk of allergy, since 24/8/2023 anyone who works industrially or professionally with products containing 0.1% or more diisocyanates by weight, or who supervises such work, must complete training. The obligation arises from Commission Regulation (EU) 2020/1149 (REACH, Annex XVII, entry 74). More about isocyanates and mandatory training

More about isocyanates