How to fit sound deadening and insulation

1Prepare the surface (all products)

1. Remove the trim panels (door cards, linings, carpets) to reach the bare metal.
2. Clean bare metal thoroughly: remove all dust and grease with panel thinners or an alcohol-based cleaner, and let it dry. Don’t use white spirit or similar products that leave an oily residue. Inside doors there is often a layer of wax: clean that off too. On plastic trim, use isopropyl alcohol (test a hidden spot first): strong thinners can damage some plastics.
3. Let the surface dry, then measure and plan each piece.

Don’t cover: door drain holes, window glass and regulator paths, lock rods and handles, airbag modules and yellow SRS connectors, seat-belt mechanisms, wiring plugs, or bolts you may need later. Mats won’t stick to underseal, bed-liner or rust. Don’t disconnect anything related to airbags unless you know the procedure.

2Fit the sound deadening mats (layer 1)

Careful: the foil edges are sharp and can cause cuts. Wear gloves.

1. Work at +16 to +18 °C or warmer. Keep the mats indoors until you use them, and warm the van or garage. If it’s still cold, warm the mat and panel gently with a hairdryer. Don’t overheat the butyl, and keep any heat away from plastic trim, wiring and foam.
2. Cut the mat to shape. With the 2mm roll, measure and cut lengths on a board.
3. Peel off the backing (on long pieces, a little at a time) and press the mat onto the bare metal.
4. Roll it down firmly with a metal roller, from the centre out, until there are no air bubbles. Keep rolling until the embossed pattern flattens out: that shows the mat is fully bonded. Use firm, even pressure; you don’t need to force it or tear the foil.
5. Cover at least 50% of each panel, starting in the centre of the largest flat areas. Knock-test as you go: when the panel sounds dull instead of hollow, it’s done. Small gaps between pieces are fine; you can butt them up or overlap slightly.

Products: 1.5mm · 2mm · 3mm · 4mm mats · 2mm roll

3Fit ST-Mat or PPE ECO foam (layer 2)

ST-Mat

One chance: ST-Mat is very sticky. Once it’s on, it can’t be removed without damaging it.

1. Clean the surface with panel thinners or an alcohol-based cleaner. Don’t use white spirit.
2. Cut the exact shape first.
3. Peel back one corner of the backing and stick that corner down.
4. Slowly peel away the rest of the backing while pressing the foam on.

Press ST-Mat down over its whole area, with no air pockets, and butt each piece tightly against the last: air gaps behind closed-cell foam can collect condensation in a van. On roofs and other overhead panels, check the edges after the first hot day and re-press any that lift.

Under a plywood floor without battens, use only 3mm ST-Mat: it’s a soft foam, and thicker layers compress over time so the ply flexes. See the van floor project.

PPE ECO closed-cell foam

1. Clean and degrease the surface.
2. Cut the sheet to size. PPE works best on flat surfaces.
3. Peel off the backing and press it firmly into place.

Products: ST-Mat (3 to 25mm) · 4mm PPE ECO · 8mm PPE ECO · 8mm PPE ECO with foil

4Fit acoustic felt or foam (layer 3)

1. Check the area stays dry: felt and acoustic foam are for dry areas only.
2. Clean the surface of dust and grease.
3. Cut to shape with a sharp knife (or scissors for felt).
4. Peel off the backing and press firmly into place. With felt, add more layers to fill deeper gaps.
5. Don’t cram it: felt and acoustic foam absorb best when they’re not squashed flat. Fill the space, but let the trim close without force, and keep it clear of moving parts.

Products: 8mm felt · 12mm felt · Autoshim acoustic foam

5Stop rattles and refit the trim

1. Clean the contact areas on the plastic parts.
2. Cut the anti-squeak tape to length, peel off the backing and press it firmly on: Madelin tape (1mm) for tight joints and trim clips, Black Layer tape (5mm) between trim and the body.
3. On cars, refit the plastic water shield behind the door card (re-seal it with butyl tape if needed), or cover the access holes with mat. Check the window winds fully up and down, the locks work and the drain holes are clear before you clip the trim back on.
4. Refit the metal partitions and trim panels.