Floors and ceilings - modern

The way floors were built stayed pretty much the same until the 1960s when multi-storey and system built housing was built from concrete with concrete floors. More recent timber and steel frame buildings have a different floor construction again. This articles deals with floors in buildings after 1960.

Floor construction

Floors between flats were usually made from timber joists which spanned between front and back walls. Secondary support beams or internal load-bearing walls reduced the span.

On the ground floor, shorter joists were used, resting on sleeper or dwarf walls.

Dwangs (known as noggins in England) or herringbone struts were used to stiffen the joists.

Floorboards were nailed to the joists. These were tongue and groove and secret nailed through the groove.

Floorboards may have been replaced with sheets of chipboard – which can make access for repairs tricky.

At hearths and at entrances a stone slab was laid on the joists.

Deafening boards were fixed between the joists to carry sound deafening material, usually a 75mm layer of dry ash and shells. This gave mass to the floor construction which helped with sound reduction.

In properties built between 1930 and the early 1940s, ash deafening material was less commonly used. Instead, a 30mm insulation quilt was laid over the joists and the timber floor nailed onto the joists [John – through the quilt?].


Ceiling construction

In older tenements, ceilings may be fixed to the floor in one of two ways. The first way, used mainly in Georgian tenements in Edinburgh (see H4.2 drawing) would have a lath and plaster ceiling suspended on a secondary timber frame or ‘branders’ hung from timber ties secured to the joists above. This separation helped to reduce sound transmission. 

The second method, used mainly in Glasgow tenements (see H4.1 drawing) was to fix the ceiling directly to the joists.  This gives a smaller floor depth.

In properties built between 1930 and the early 1940s, lath and plaster ceilings were less commonly used with two layers of plasterboard being used instead. This type of construction is not as good at reducing noise.


Rot in floors

Problem: If your floors are bouncy, it may indicate rot in the joist ends. Joist ends are set directly into the walls. If the walls get damp, this can allow joist ends to rot.

Solution: New ends can be spliced onto the joists. The new ends should be wrapped in a damp proof membrane before being inserted into the wall to help prevent rot in the future.


Sloping and uneven floors

Problem: Localised subsidence can lead to sloping floors.

Solutions: This can be fixed by lifting the floorboards and nailing new joists to the side of the old. Floorboards can then be replaced. A floating floor (also a solution to noise) can be used.

Weakened joists

Notches are often cut in joists to allow for piping or electric cabling to be installed.  Large notches can reduce the strength of the joist.  Ideally, cables and pipes should be lead through holes drilled in the centre of joists.

Noise problems

  • Floorboards have been lifted during repairs and the original deafening material removed or replaced with glass wool which has very little mass and little effect on reducing noise.
  • Joists which run parallel to a wall often have an air gap, allowing sound to travel between ceiling level and skirting. (see drawing H1.2)
  • Loose or badly fitted floorboards can reduce the floor’s noise performance.
  • Notching of floor joists for pipes and services can reduce the stiffness of the floor and lead to squeaks.
  • Sanded floorboards or laminate floors laid over existing floorboards without any coverings, transmit low frequency sound such as footsteps.

A noise problem between floors may in fact be caused by “flanking” sound – noise carried by a thin internal wall to flats above and below. 

Noise solutions:

  • Replace the ash deafening. Use dry sand; sand and plaster; limestone chips and recycled waste gypsum. Mineral wool is better than glass wool, providing reasonable insulation against general living noise and speech.  It is less effective though against low frequency ‘bass’ sounds such as amplified music.
  • Use screws to fix squeaky floorboards
  • Install soft floor coverings that reduce impact noise from footsteps. Look for a bonded, soft floor acoustic grade material which is better than normal carpet underlay.
  • “Platform” floor systems can be installed. These consist of a layer of high density board with resilient foam bonded to the underside. Systems vary in thickness. These must be laid correctly to be effective. These should not touch the walls. Doors may need to adjusted.
  • “Floating” floors can be installed. “Resilient” battens with special foam bonded to one surface are laid over the existing floor and a new floor surface laid on top. To avoid a ‘drum effect’ between the new and old floors, lay a 25mm mineral wool quilt between the battens (but not under them). If the floor is uneven, special fixings called resilient cradles can be used to hold the battens. These can be adjusted in height. Services such as electrical cabling can be run within the void in both directions.
  • Floorboards can be lifted and a resilient foam laid on the joists. The gap can be filled with mineral wool or a sound absorbing material to further increase noise insulation. Floorboards are then replaced and laminated floor panels added.
  • An alternative to lifting the floorboards is to pump in a blown fibre insulation material into the gap between the joists.



  • Plasterwork can become detached – prod it with a broom stick.  Staining suggests water leaks – check for the presence of rot and make sure the heavier wet plaster is still well fixed.
  • Chemical staining from treated joists
  • Replacement plasterboard ceilings have less mass than original plaster ceilings and are less effective at reducing noise.
  • Cornicing may have been removed allowing sound to leak through the wall junctions.

If your ceiling has come down and there is a flat above you, replace the ceiling with at least two layers of plasterboard to provide fire protection.  If your old ceiling is cracked but still intact, 'brander' the ceiling with battens screwed at right angles to the ceiling joists. Sheet the battens with plasterboard and a coat of plaster.


  • If there is any movement in the ceiling, get it fixed or dangerous chunks of plaster can fall.
  • Seal staining from treated joists with special paint before decorating

Treating your ceiling to reduce noise

  • A secondary ceiling can be installed. Existing cornices will be hidden or removed.  It will also lower the ceiling height.
  • In older stone tenements an “independent ceiling” can be installed. This consists of a timber joisted ceiling (100 x 50mm timbers) secured to the room walls through an isolating strip.[John- what do we mean by this?]  The ceiling should not have contact with the existing floor or ceiling. The ceiling is sheeted with 2 layers of gypsum board, stagger jointed and the void above filled with 100mm mineral wool.  The greater the void depth the better, but it should be at least 150mm.
  • Other types of secondary ceilings using timber or metal framing can be used. These are suspended from the floor above. Ideally there should be enough space in the lowered ceiling to install some additional mineral wool. The new ceiling is then sheeted with a further two layers of plasterboard, stagger jointed and plastered to fill any voids.
  • Resilient (padded) bars directly fixed to the existing ceiling are mainly used where space is limited, or in more modern constructions.


  • Since some options might require extensive work, it is advisable to seek professional advice before agreeing any work.
  • Cornicing and skirtings are part of what makes older tenements unique If your building is listed, you may need to get consent from the Council

Dealing with cracks in ceilings

Cracks may come from movement of the building [John –taken this from Ten Hdbk, sounds scary – when is it more than a cosmetic problem?]

If plasterwork either side of the crack is well fixed, the crack can be easily fixed by scraping out the joint and refilling.

Small areas of plasterwork can be patched if there is a firm backing. Plaster board can be used to take up some of the depth before new plaster is added.

If the ceiling is to be replaced completely, it should be done properly or you may suffer from noise problems.  After removing the old ceiling (a messy job), new layers of plasterboard with staggered joints are nailed to the joists. Branders can be used to make a more even surface for fixing the plasterboard. Some builders may suggest fixing branders to the old ceiling without removing it first and then fixing plasterboard to the branders. This does work but does make it difficult to check joists later for the presence of rot.


Noise in floors: Interwar Housing and Cottage Flats

These properties suffer from many of the noise problems noted for older stone tenements.

This construction did little to reduce either impact or airborne sound as the insulation quilt compresses and disintegrates.  Sometimes 50 x 50 timber branders were installed across the joists to support the ceiling, but as they were not isolated [John, explain], this did little to improve noise insulation.