Floor screeds and finishes

A variety of possible floor repair strategies can be considered, but the choice of method very much depends on the extent of the problem as well as site constraints. Work carried out within an occupied building inevitably means a need to control noise dust and vibration, while time constraints impose other restrictions on the range of suitable materials.

CIRIA Report R184 Chapter 9 sets out some useful guidance upon the selection of appropriate repair strategies (Screeds, flooring and finishes: selection, construction and maintenance, Part 5 – Screeds, 1998). For small pockets of damage, the affected areas can be cut out and filled with a suitable rapid drying screed, of which there are a number of proprietary types. If larger areas of unsound material exist, more significant areas of replacement may require a different approach. Any investigation into localised collapse must involve consideration of remaining, apparently sound, areas to determine the likelihood of future defect.

In some cases serviceability may be restored to an unsound screed by application of a low viscosity resin to soak into the body of the screed and to consolidate it. Epoxy (or polyester) resins are expensive materials and although capable of fairly rapid application, noxious fumes need to be considered, making this form of treatment applicable only in certain conditions. If a screed is seriously compromised, and if service conditions are demanding, impregnation treatments may not be appropriate anyway, as they may still fail to deliver satisfactory performance.

Assuming total replacement with a new screed is not practicable or desirable, another alternative might be to apply a flowing restoration screed. These proprietary products can often be laid down to about 3mm thickness (although it is difficult to see what meaningful benefit could be achieved at this thickness). A nominal thickness of 10mm would be more usual. These products are relatively expensive, although the savings in time and disruption may mean that when considered in the round, they can provide a more cost-effective alternative than full screed removal and replacement. Flowing screeds are specialist applications and in most cases specialist advice is needed in selection and application

Providing an additional thickness of screed has related effects - adjustments to door heights, skirting boards, floor boxes and the like and so may not be suitable in all cases.

If full replacement of the screed is the only option, cementitious screeds should be selected and specified with great care to avoid problems of cracking, delamination and failure. Drying time is likely to be a problem in refurbishment works and so proprietary quick drying screeds may be preferable to conventional mixes.