4mm x 25mm Double Countersunk Chipboard Screws | Box of 200

Description

The Tekwarm 4mm x 25mm Chipboard & Woodscrew is a double countersunk, wax lubricated single thread screw for fixing overlay boards over Tekwarm routed chipboard and OSB underfloor heating panels. Each box holds 200 screws.

The double countersunk head reduces the likelihood of head shear and helps the screw sit flush, while the 40 degree deep single thread gives a secure fixing with high pull-out resistance and the 25 degree sharp point gives a fast start. At 25mm long, the screw suits 9mm overlay boards, leaving 16mm of thread in the panel below.

4 x 25mm

Screw size

200

Screws per box

Double

Countersunk head

Wax

Lubricated thread

40°

Deep single thread

25°

Sharp point

Keep every screw clear of the heating pipe

Overlay screws go in after the pipe is laid. Pre-drill near the channels, position each fixing so it cannot touch the pipe below, and keep screws at least 50mm away from any pipe run when fixing the Tekwarm 9mm overlay, at maximum 300mm centres.

Match the screw length to the overlay thickness

Use 25mm screws for 9mm overlay boards. The Tekwarm 6mm HDF overlay is specified with 20mm screws (34 per board), and routed panels are fixed to joists with 70mm screws. Do not use a screw that is long enough to reach the pipe.

Recommended for Tekwarm overlay boards

Fixing screws for routed chipboard and OSB systems. Countersink so heads sit flush and the finished surface stays flat for the floor finish.

Key features

Double countersunk head

Reduces the likelihood of head shear and assists the completion of countersinking.

Wax lubricated

Wax lubrication speeds insertion, adds extra driving torque and improves resistance to corrosion.

40° deep single thread

A deep single thread provides a secure fixing with high pull-out resistance.

25° sharp point

A sharp point and single lead give a fast start and improved thread acceptance.

Timber and man-made boards

A single thread woodscrew for timber and man-made boards, or masonry with a plastic plug.

200 per box

Box of 200 covers many overlay boards on larger floors.

Technical specification

Product details

Brand

Tekwarm

Product

Chipboard & Woodscrew, double countersunk

Size

4mm x 25mm

Quantity

200 per box

Screw features

Head

Double countersunk

Finish

Wax lubricated

Thread

40 degree deep single thread

Point

25 degree sharp point, single lead

Suitable for

Timber and man-made boards; masonry with a plastic plug

Usage with Tekwarm systems

Intended use

Fixing overlay boards over routed chipboard and OSB panels

Suited overlay

9mm overlay boards (25mm screw: 9mm board plus 16mm into the panel)

Fixing pattern

Maximum 300mm centres on the 9mm overlay, drilled and countersunk

Clearance from pipe

No screws within 50mm of any pipe run

Frequently asked questions

What are these screws used for?

They fix overlay boards over routed chipboard and OSB panels once the heating pipe is in place, such as the Tekwarm 9mm moisture resistant overlay board.

Which overlay should I use them with?

The 25mm length suits 9mm overlay boards. The Tekwarm 6mm HDF overlay is specified with 20mm screws, so choose that length for the 6mm board.

How far apart should I fix the overlay?

For the Tekwarm 9mm overlay, drill and countersink the fixings at maximum 300mm centres, keeping screws at least 50mm from any pipe run and making sure no pipe is pierced.

Why a double countersunk head?

It reduces the likelihood of head shear and helps you countersink the screw cleanly so the surface stays flat for the floor finish.

What is the wax lubrication for?

It makes the screw go in faster with extra driving torque and improves resistance to corrosion.

How many screws are in a box?

Each box contains 200 screws.

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Room Dimensions

Length (in m):

Width (in m):

Height (in m):

Room Type

Living Room

Bedroom

Kitchen

Bathroom

Conservatory

Hallway

Glazing Type

Single Glazed

Double Glazed

Triple Glazed

External Walls

0 Wall

1 Wall

2 Walls

3 Walls

4 Walls

Insulation Level

Poor

Average

Good (New Build)

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Required Heating

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Watts

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BTUs