Indy Total Construction

Taking down an old lath-and-plaster ceiling is an extremely dirty and dusty job, so before you start you must take the necessary action to protect both yourself and the other rooms in the house.

Protective clothing is essential and you will need to wear overalls, safety goggles, a facemask and thick gloves. But the most important item is a construction worker’s hard hat, which you can rent or buy. Hopefully the ceiling will come down under your control, but it is as well to be prepared for unexpected falls.

Because so much dust will be flying about, strip the room of all furnishings and seal the connecting doors to other rooms with plastic sheets or old blankets. It is a good idea to spread a large, thick plastic sheet across the floor to make collecting the debris easier, and you should have a good supply of thick plastic sacks to hand for bagging up the rubbish. If the ceiling is very large, it may be worthwhile renting a small container to dispose of the old ceiling.

You need to be able to reach the ceiling easily so that you can lever sections of it away from the joists. For simplicity, place a scaffold board between two step ladders so that your head will be about 6in from the ceiling — a ladder on its own is not suitable. An alternative is to rent sections of scaffold tower to make small access platforms, but this is probably only worthwhile if the job is large.

Any ceiling-mounted lighting fittings must be

removed (after turning off the power at the service panel or removing the appropriate fuse). Pull the supply cable back above the ceiling if you can get to it; if not tape up the ends and leave it hanging.

If the ceiling is immediately below the roof space, check that there are no other electricity cables lying across the top of the ceiling which you may snag as you remove it. Clip these to the joists.

Any dirt and dust above the ceiling should be removed with a vacuum cleaner.

Many attics are insulated with various materials laid across the top of the ceiling and obviously, these must be removed. Roll up glass fiber mat insulation and put into plastic garbage bags stacked in an unaffected part of the attic until it can be replaced. Loose-fill insulation should be scooped up and poured into garbage bags; or suck it up with an industrial vacuum cleaner before bagging it.

You can use a large claw hammer or a flat chisel and hammer to remove the old ceiling, although you might find the former easier as the latter will mean holding both arms above your head, which can be very tiring.

Hack into the plaster, levering pieces away until you have exposed a large area of laths. Prise these from the joists, always working away from yourself so that any falls will not be on top of you.

Continue working across the room until the entire ceiling is removed. Using pincers, pull out all the lath-fixing nails from the joists. Work round the edges of the ceiling with a chisel to clean up the plaster on the walls.

The first job is to remove the old floor and dig out the ground below to at least 12in below the final floor level. Lever up an old wooden floor and saw through the joists for easy removal. Then demolish the dwarf walls. Break up a concrete floor: the best way is with a rented jack hammer. Keep the rubble for use as a bed for the concrete later. Wear stout boots, thick gloves, overalls and safety goggles.

Find the flashing in the walls; it may be a layer of slate or bitumen, or one or two courses of engineering bricks. If necessary, chip away the plaster to find it.

If the floor in the next room is of suspended wood, lay plastic drain pipes between any airbricks and the inter-connecting door threshold, setting them in place with bits of stone or brick: this is vital to provide ventilation throughout the floor. Build a retaining wall across the threshold with concrete building blocks.

Next make up some datum pegs from 2 x tin sawn softwood marked with the depths of the bed and concrete subfloor layers: 6in and 4in respectively. Cut a point on one end of the pegs then drive a peg into the ground near a given reference point, to indicate the surface of the floor. Drive the other pegs in at 3ft intervals, checking that their tops are level with the first.

Put down the brick and stone bed, leveling it with the marks on the pegs and compacting it well with a purpose-made tamper. Spread a layer of damp builder’s sand over the top to fill any voids.

The concrete for the subfloor should be of 1 part cement: 21/2 parts concreting sand: 4 parts gravel.

Lay the concrete so that it is level with the tops of the pegs, tamping it down well and drawing a stout batten across the tops of the pegs to level it. Fill any hollows with more concrete then tamp again.

When the concrete has cured, lay the cleavage membrane. With bitumen emulsion apply about three coats, taking it up the wall to the flashing. If plastic sheet is used, tack it to the walls above the flashing. Fold the corners and overlap the sheets by 8 to 12in, sealing the join with building adhesive.

Use 1 x 2in battens to divide the floor into 3ft wide bays for the finishing screed. Set them in place with dabs of mortar, level if necessary by packing offcuts underneath: check with a spirit level.

Fill the bays with a 3:1 mortar mix and draw it off level with a straight-edged batten held across the tops of the dividing battens. When two bays have been completed, lift out the batten in between and fill the resulting slot with mortar. Then trowel both bays smooth with a metal trowel. When the mortar has stiffened, give it a final polish with a wetted trowel.