Become a partnerReplacing old carpet: removal and subfloor preparation
Replacing old carpet may sound straightforward, but the comfort and appearance of the new covering depend heavily on the floor beneath it. When replacing broadloom carpet, inspect the old layers and the subfloor before installing the new material. This prevents old odours, bulges and soft spots from being hidden under a new surface.
1. Plan before starting
Measure the room and note door clearances and the height of adjacent floors. Allow for the combined thickness of carpet and underlay. Planning seam positions in advance helps reduce unnecessary cuts and waste.
Remove furniture and finish painting and other dusty work. Vacuum the old carpet. Agree who will remove and dispose of it. Check the new roll's colour, pattern and visible condition before cutting.
2. Identify how the old carpet is fixed
Carpet may be fully bonded, stretched onto perimeter grippers or installed by another method. Check a small corner first. If needed, cut the carpet into manageable sections without damaging the floor below. Wear gloves and collect exposed nails and fixings promptly.
Do not automatically reuse the old underlay. Replace material that is compressed or damp, and check that any apparently sound underlay is compatible with the new carpet and installation method.
If you uncover very old layers or adhesive of unknown composition, do not start sanding them. Some older floor coverings and mastics may contain asbestos. Appearance alone cannot establish whether a material is safe; have suspect materials assessed by a specialist.
3. Check five things about the subfloor
| Check | What to look for |
|---|---|
| Dry | Are there damp patches, odours or leaks? Touch alone cannot establish whether concrete is dry enough; use an appropriate moisture test. |
| Sound | Is the concrete crumbling, or are boards moving? Gluing over a weak surface does not solve the problem. |
| Smooth | Are there adhesive ridges, hollows or abrupt steps? These may be felt through the carpet. |
| Clean | Dust, grease, paint and loose residue must not interfere with the new adhesive bond. |
| Stable | Does any part flex or squeak underfoot? Find and correct the cause before fitting the new carpet. |
4. Match preparation materials to the substrate
Repair loose or weak areas in concrete, then use compatible primer and smoothing compound where required. Timber subfloors need materials approved for that construction. Pouring ordinary cement compound over moving boards is not a reliable solution.
Check compatibility before applying new adhesive over old residue. Follow the selected primer, smoothing compound and adhesive instructions for removal or preparation. Find the cause of moisture or contamination rather than masking odours, and allow repair layers to dry for the specified time.
5. Use the correct installation method
Broadloom carpet and carpet tiles are installed differently. Adhesive, stretching, underlay and edge details depend on the specific product. Securing an entire room with double-sided tape around the edges is not suitable for every carpet.
Follow acclimatisation instructions. Check pile direction and pattern alignment: the same colour can look different when laid in another direction. Observe adhesive waiting and curing times, and do not return furniture too early.
Before accepting the work
Walk around the room and check for bulges, loose areas, lifting edges and door clearance. A seam may remain visible, but its edges should not open. Ask when the first cleaning is permitted and how the carpet should be maintained. Compare available options in the broadloom carpet section.