UNDERLAY - Ceramic tile underlay | 1800 x 900 x 6mm

Features

Key Features

Provides a stable base for tiling over timber floors
Helps prevent tile and grout cracking due to floor movement
Lightweight, easy to cut, and simple to install
Sized for efficient coverage: 1800 × 900 × 6 mm
Suitable for internal dry areas
Meets NZ building code for tile substrate prep

Where to use it?

Use it when you're working with:

Timber floors in bathrooms, kitchens, and laundries
Residential renovations or new builds
Areas where movement or deflection may affect tilework
Projects that need a compliant tiling base over wood substrates

How to use?

How to Use (Mixing & Application)

Over Timber Subfloors

Fixing:

Lay with staggered joints over the timber floor
Fix using approved nails or screws at recommended spacings
Tape joints if required for added stability

Tip: Always check that the timber floor is dry and structurally sound before laying underlay.

Compatible Surface

Plywood
Particleboard
Timber flooring

Tongue-and-groove wooden substrates (with correct prep)

Appearance

Fibre-cement board, 1800 × 900 × 6 mm sheet

Pro Tip

Always leave a 3 mm expansion gap around the perimeter of the room—this gives the underlay space to move and reduces the chance of lifting or cracking later on.

Key Features

Provides a stable base for tiling over timber floors
Helps prevent tile and grout cracking due to floor movement
Lightweight, easy to cut, and simple to install
Sized for efficient coverage: 1800 × 900 × 6 mm
Suitable for internal dry areas
Meets NZ building code for tile substrate prep

Where to Use It

Use it when you're working with:

Timber floors in bathrooms, kitchens, and laundries
Residential renovations or new builds
Areas where movement or deflection may affect tilework
Projects that need a compliant tiling base over wood substrates

How to Use (Mixing & Application)

Over Timber Subfloors

Fixing:

Lay with staggered joints over the timber floor
Fix using approved nails or screws at recommended spacings
Tape joints if required for added stability

Tip: Always check that the timber floor is dry and structurally sound before laying underlay.

Compatible Surfaces

Plywood
Particleboard
Timber flooring

Tongue-and-groove wooden substrates (with correct prep)

Appearance

Fibre-cement board, 1800 × 900 × 6 mm sheet

Pro Tip

Always leave a 3 mm expansion gap around the perimeter of the room—this gives the underlay space to move and reduces the chance of lifting or cracking later on.

Frequently Asked Questions

1. What is this underlay used for?
It’s a fibre-cement sheet used under tiles on timber floors. It helps create a stable base and reduces the risk of tile cracking.

2. Can I use it in wet areas?
It's suitable for dry internal areas. If you’re working in wet zones like showers, a waterproofing system should be applied over the underlay.

3. Is it compatible with underfloor heating?
Yes, but always check the heating system's specs and follow best-practice installation guidelines for layers above and below.

4. How do I fix it to the timber floor?
Use corrosion-resistant nails or screws, with fixings spaced according to manufacturer guidelines. Stagger the joints for strength.

5. Do I need to tape the joints?
Taping is optional but recommended for added strength and stability, especially in high-movement areas.

Shipping and Return Policy

At Surtec, we aim to make your experience as seamless as possible. Orders are processed efficiently through our Auckland branches and distributed nationwide via our growing logistics network. For any queries about delivery times, product availability, or returning an item, feel free to get in touch with our team. We're here to help you keep your projects moving.