Phase 2: Installing the Wunda Rapid Response® Boards and Pipe

STEP 1: Perimeter Strip (Optional)

Perimeter strip creates a barrier between the edge of a Rapid Response® board and the wall to create an expansion gap and minimise heat loss.

When is perimeter strip required?

• If the final floor finish is intended to be wood, engineered wood, or laminate laid floating with XPS breathable underlay, your floor finish does not require perimeter strip. Skip to Step 2.
• If the intended floor finish is carpet laid on top of Wunda duo boards, fit battens around the perimeter of your room before fitting the Rapid Response® boards. Your floor finish does not require perimeter strip. Skip to Step 2.
• If the final floor finish is tile or stone, or requires self-levelling compound, you will need to fit perimeter strip and complete this step.

How to fit perimeter strip:

Before laying the Rapid Response® boards, remove skirting boards and trim any doors to accommodate the depth of the boards and final floor finish.

Fit perimeter edge strip around the outside edges of the area to be heated using the adhesive backing. Any excess height can be trimmed off once the final floor finish has been laid and before refitting the skirting boards.

Optional Materials Needed:

• Perimeter strip
• Battens

Refer to step 5 in phase 1 for tools and materials.

Battening for carpet & the use of vapour barrier if required:

When laying carpet over a completed and pressure-tested system, fix a wood batten around the perimeter of your room, including the doorway. Use a batten the same height as your Rapid Response® boards. This will give the door thresholds and carpet grippers something to be fixed to.

After pressure testing, lay the vapour barrier across the Rapid Response system. Fix carpet grippers to the battens through the vapour barrier. Do not fix through the panels or pipework. In doorways, battens can be cut to allow pipes to pass.

Take care to avoid damaging the pipe when using carpet grippers and door bars, especially where pipework transitions through the doorway.

STEP 2: Dry lay boards

Review your supplied Wunda board & pipe layout drawing before starting. If in doubt, contact Wunda customer support.

Dry lay boards onto the floor, making any necessary cuts with a fine-tooth saw or craft knife, using a straight edge rule to assist in making straight cuts.

Take care when cutting the boards; wear work gloves as the aluminium can be sharp. Keep any offcuts as they may be useful in other areas. If you cut boards incorrectly, you can bond the two halves in a main panel area.

Materials Needed:

• Pipe layout plan
• Rapid Response® Boards
• Fine tooth saw / craft knife
• Straight edge rule
• Work gloves
• Marker pen
• Drill
• Pipe conduit

Refer to step 5 in phase 1 for tools and materials.

Using a marker pen, mark any areas that may need routing for additional pipe channels, keeping a gradual radius (bend) no sharper than found on the main boards.

(Optional) Before fixing board in place: If the pipe layout design shows pipes running through walls, mark where the pipe channel aligns with the wall and drill suitably sized holes (pipe conduit is 25mm) before fixing the boards. Use a pipe conduit or sleeve to allow free movement of the pipe within the wall. Take care not to drill through any pipework or cables within the wall. If there is an unforeseen obstruction, contact Wunda customer support.

STEP 3: Bonding the board in place

It is necessary to warm WundaSpray adhesive cans in warm water and then shake vigorously for the propellant to mix with the adhesive. Failure to do so may result in 'spattered' spraying, causing a weaker bond and less coverage.

Please ensure you have followed the Phase 1 preparation guide to ensure the floor is level, stable, and dry. Do not bond the boards to asphalt or bitumen subfloors.

Remove any dust or debris created from cutting the boards.

Make sure boards are in the correct place, as they are very hard to move once bonded without damaging the boards.

Suitable for bonding to concrete, screed, and wood. If in doubt, contact customer support and always try a patch test first.

Ensure you are working in a well-ventilated area and using a protective mask.

Use WundaSpray adhesive to bond the boards to the subfloor. The boards need to be secured next to each other with no gaps between them.

Use a small off-cut of pipe to ensure the pipe channels line up.

Ensure all boards are securely bonded before proceeding. If movement is detected, it may be due to insufficient warming of the adhesive or incorrect spray pattern. In such cases, fix the boards in place using stainless steel screws and large washers at a 300mm spacing.

Understanding transitional boards:

Transitional boards are needed when a high density of pipe is required to run through areas such as a hallway, enabling multiple pipe loops to run side by side from the manifold into the room they are serving. They are made from the same high-density EPS material as the Wunda Rapid Response® board and have multiple pipe channels that can be cut and shaped as required by the floor layout plan.

They bond to the subfloor using WundaSpray adhesive. Where transitional boards are required at a corner, two opposite 45-degree angles provide a 90-degree turn. Leaving a gap of approximately 120mm allows the pipe to be formed and bent around the corner as it changes direction from one straight channel to another without kinking the pipe.

Materials Needed:

• WundaSpray board adhesive
• Rapid Response® boards
• Mask

Refer to step 5 in phase 1 for tools and materials.

STEP 4: Preparing the boards for pipe

To ensure the pipe is fully supported, the gap and boards can be back-filled using a levelling screed such as Mapie ultraplan renovation screed or Ultra-floor Level It 2. Alternatively, use a plain board in this section and a router to cut the necessary corners.

With boards firmly secured, use a router set at the appropriate height (16/12mm) to route any additional channels required as marked. Vacuum any debris on boards and in pipe channels.

Materials Needed:

• Router
• Vacuum

Refer to step 5 in phase 1 for tools and materials.

STEP 5: Lay the Pipe

Preparation:

Review your supplied Wunda board & pipe layout drawing to identify manifold location and pipe routes, and the length of pipe for each loop. Some shorter loops may share a longer coil.

Referring to the pipe layout drawing, prepare to lay the first loop of pipe. Some channels may need cutting with a craft knife.

Cut the very end of the pipe carefully to remove air pressure, ensuring it is pointed downwards and away from anyone. Make sure to cut the end straight.

Ensure you are using the correct length coil supplied. Mark on each loop with the loop number and whether it is the flow or return. This will be important when connecting to the manifold. The flow is identified by a red dot, and the return end by a blue dot.

When laying the pipe:

Start at the manifold location, allowing approximately 1m excess pipe up the wall for your flow, and on your return to the manifold location, allow 600mm for the return fitting. You may wish to mount the manifold at this stage (see phase 3).

Following the pipe layout, lay the pipe securely into the channels in the boards.

A tip is for one person to lead with the coil, whilst another walks behind ensuring the pipe is secure into the channels.

Any areas where the aluminium has been perforated will snap through as the pipe is walked into the channel and fold down in contact with the edge of the pipe.

Rotate the entire coil 180 degrees when the loop returns at the end of each run to ensure the pipe does not try to twist, and that the tension in the pipe is pushing down into the floor so it does not try to raise up and out of the channel.

If the pipe pushes out of the channel, it can be carefully tapped down using a wooden batten across the board with a hammer and some aluminium tape to secure it in place.

Do not try to force tight bends into the pipework, as this may cause it to kink.

If a kink occurs, wrap it in a cloth to protect it and gently reshape with pliers, being careful not to damage the pipe.

Repeat these steps to lay all of the pipe runs as per your pipe layout drawing.

If any pipes need to be run through walls, have one person feeding the pipe through the wall while another draws it from the other side, to avoid kinking the pipe.

Materials Needed:

• Pipe layout plan
• Pipe
• Craft knife
• Pipe cutter
• Marker pen
• Manifold

Refer to step 5 in phase 1 for tools and materials.

STEP 6: Prepare for your floor finish

Installing floor probes for wood and laminate floor finishes:

If you will be laying a temperature-sensitive floor covering such as wood or laminate, a temperature sensor floor probe will need to be installed.

The floor probe must be placed so that it will be in contact with the underside of the floor covering. The aluminium on the Rapid Response® board around the sensor end must be peeled back so that the sensor is not touching.

A thin channel must be cut, allowing the probe cable to pass across the floor and at a sufficient height up the wall for it to be connected to the wall thermostat. Choose an area of the wall for your thermostat that is not in direct sunlight or near a source of heat.

If you are installing any floor finish on top of an approved screed / levelling compound, the floor probe will need to be fitted later once the screed has cured.

Diagram showing: Minimum 10mm levelling compound above UFH pipe, Overfloor board, Floor probe located at uppermost surface.

Prepare unused pipe channels:

Depending on your choice of floor finish, an approved self-levelling compound may be needed as an intermediate layer. Please see the floor covering information document for recommendations.

When using a self-levelling compound, ensure the aluminium of all unused pipe channels is cut to expose the empty channel, ready for filling with your chosen levelling compound.

Before moving onto phase 3, ensure the pipe runs are continuous with no joins. Ensure all boards are firmly in place and pipe is flush and secure in the pipe channels.

If you are planning on installing a temperature-sensitive floor finish, remember to install a floor limitation probe. The end of the probe needs to be in contact with the underside of the floor finish. If using a self-levelling compound, this will need to be installed after pouring the levelling compound following a successful pressure test.

Once phase 2 is complete, proceed to phase 3.