Removal of old wooden parquet flooring (nailed, bitumen-bonded)

The way the parquet is fixed decides the tools, the amount of work and what the subfloor will look like afterwards. The easiest way to find out is to remove a threshold strip or a loose block near the wall and look underneath.

• Nailed parquet usually sits on a timber base, such as floorboards or a timber subfloor in older houses. On the edge of the strips you will find thin nails driven at an angle through the tongue. This type comes up faster, but you need to take care of the timber underneath.
• Bitumen-bonded parquet is common in older flats and houses with concrete floors. Under the block you will see a hard, black, often shiny layer on the screed. Bitumen holds very firmly, and once the blocks are up it still has to be removed from the subfloor.
• Parquet bonded with modern adhesive has a lighter adhesive underneath, which can be flexible or hard. The process is similar to bitumen, but the residue behaves differently when sanded.

In practice it often turns out that one flat has more than one method, for example patched areas near radiators or in the hallway.

The job starts with preparing the room. Furniture and rugs come out, and skirting boards and door thresholds are removed. Door frames and doors are covered with film or cardboard so they do not get scuffed. If the doors will later need trimming to suit the new floor height, it makes sense to take them off their hinges straight away.

With nailed parquet, work starts at a wall or in a corner where the strips lift most easily. The first row is levered up with a pry bar, and the rest follow row by row. Nails left in the subfloor are pulled out or knocked flush so nothing sticks up. Valuable old parquet can be lifted carefully, in the reverse order to how it was laid, and reused.

Bonded parquet is chipped off with a bolster chisel or a wide scraper, often with a demolition hammer fitted with a scraper blade. The blocks usually break in the process, so reusing them is rarely possible. Next comes removing the bitumen. This is done mechanically, with a scraper and a floor sander, or with an adhesive remover used according to the manufacturer's instructions. Finally the subfloor is thoroughly vacuumed.

At the end, the subfloor is assessed: is it firm, dry and flat enough? That decides whether local repairs with a levelling compound are enough, whether a full self-levelling screed is needed, or, on a timber base, whether something like OSB boards should go down.

How demanding the job is, and therefore what it costs, depends on a few things you can check before work starts:

• Fixing method: nails are simpler, while bitumen and hard adhesives are much slower
• Thickness and amount of bitumen: the more of it is left on the screed, the longer the sanding takes
• Room shape: a large rectangular room goes quickly, a hallway with many corners, door frames and radiators goes slowly
• Condition of the subfloor: soft or crumbly screed is easily damaged by chiselling, and rusty nails tend to snap
• Access and waste: an upper floor without a lift, carrying sacks downstairs and taking them to a recycling centre or a skip

Lifting parquet is dusty and noisy. Wear a dust mask or respirator, safety glasses, sturdy gloves and work boots. Seal the room off from the rest of the home with plastic sheeting, and use a sander with dust extraction when grinding off bitumen.

Take care with old black adhesives. Older buildings sometimes used tar-based adhesives that can contain harmful substances, and some black bitumen adhesives also contained asbestos. If you are not sure, have a sample tested by an accredited laboratory. Materials containing asbestos may only be removed by a licensed or qualified contractor, depending on local rules. Do not burn wood with bitumen, varnish or adhesive on it in a stove or open fire. It belongs at the household waste recycling centre or in a builder's skip.

In a flat, tell the building management or the owners' association in advance. They usually have rules on noisy work, permitted hours and where a skip may stand. Replacing a floor covering is normally ordinary maintenance. If you plan to change the floor build-up, touch load-bearing parts or alter pipes and cables in the floor, check with your local building authority what is required.

You can manage nailed parquet in a small room yourself. With bitumen and large areas the work is very hard physically and there is a real risk of damaging the screed, so calling a flooring contractor is more sensible there.

1. Clear out the furniture and remove the skirting boards and thresholds.
2. Cover door frames and doors with protective film or cardboard.
3. Put on a respirator, safety glasses, gloves and sturdy footwear.
4. Start at a wall and lever up the first strip with a pry bar over a wooden block so the subfloor is not damaged.
5. Work row by row and put the strips straight into sacks or onto a pile outside the room.
6. Pull out or knock flush any nails sticking out of the subfloor.
7. Sweep and thoroughly vacuum the whole area.
8. Check the subfloor for firmness, cracks, damp and loose boards.
9. Take the waste to the recycling centre or order a skip.

• Prying and chiselling too roughly. Deep gouges in the screed or broken boards underneath then need repairing, and preparing for the new floor takes longer.
• Leaving bitumen residue on the subfloor. New adhesive does not hold on it, and bitumen can bleed through or react with vinyl over time. Whether anything can go over the residue is decided by the technical data sheet for the new floor and the primer.
• Skipping the flatness check. A floating floor or vinyl on an uneven base creaks, flexes and the joints can open up.
• Missing the damp. Old parquet sometimes hides damp screed or rotten timber. Deal with the cause first, then lay the new floor.
• Working without protection. Dust from bitumen and wood irritates the airways, and splinters with nails in them cause injuries easily.

Before the new floor goes down, go over the subfloor with this list:

• No strips, nails or protruding staples are left on the surface
• Bitumen and adhesive are removed to the extent the new floor requires
• The subfloor is firm, does not crumble and does not sound hollow when tapped
• A timber subfloor does not flex and the boards are firmly fixed
• Under a two-metre straightedge there are no larger gaps than the new floor's manufacturer allows
• The screed is dry, ideally confirmed with a moisture meter
• The area is vacuumed and free of dust
• Door frames, doors and walls are undamaged
• The waste has been taken away and the room is clean