Code of practice for installation of laminate floor coverings

BS 8425-2003 pdf free.Code of practice for installation of laminate floor coverings.
In order for the correct floor covering to he installed in appropriate conditions, at the right time, etc., it is essential that all parties have a clear understanding of the requirements of the project, e.g. new build or refurbishment, and of the implications for all concerned.
To ensure that this is achieved, it is essential that there is wide consultation between all parties involved in the project. including sub-contractors and materials suppliers. This consultation should start early in the design stage but will be necessary throughout the contract, especially should requirements or time scales change and as new sub-contract work is initiated.
As each project will be unique, it is impossible to give a definitive list of the information to be exchanged. but the following (4.2 to 4.9) are typical examples.
4.2 Project
The name and location of projects and personnel involved in pre-contract negotiations should be identified.
4.3 Contract conditions
A programme for commencement and completion of work should be defined, including any specific
requirement for sequenced completion.
4.4 Special attendance
Access, unloading, hoisting and storage facilities, heat, light and power and any additional items
considered necessary to expedite the work should be provided.
4.5 Design
4.5.1 General
The following layout and specifications, based on building type and occupational uses, should be provided:
a) type of use: building, rooms;
b) type and density of foot and/or wheeled traffic;
c) specific requirements: fire resistance period, acoustic absorption level;
d) particulars of use: staining, potentially abrasive conditions.
4.5.2 Floor details
The completed drawings/specification should provide comprehensive information on:
a) whether upper floor, ground floor or below ground level;
b) whether ground-supported or suspended construction;
c) particulars of any under floor heating installation or security installation;
d) position and treatment of expansion joints;
e) curing and drying times of screeds and bases likely to be required before the installation ot Iloor coverings;
0 screed or base with finished floor level, permissible departure from datum and class of surface regularity required:
4.5.3 Barrier zone
Entrance flooring systems should be used to reduce the dirt, grit and water carried into the building by foot traffic, hence they will reduce wear and the risk of slipping when the building is in service. The size. position and design of the barrier zone should be considered at the design stage, but preferably should be a minimum of three metres to be effective. Barrier zones should conform to BS 7953.
4.5.4 Associated detail8
Details of abutments, skirtings, services (embedded or sleeved), movement joints, separating strips, pattern or border details and junction with other adjacent flooring should be provided.
4.6 Testing
Details of an’ conformity testing of the base. screed. floor covering. etc. that is to be conducted and the party which is to be responsible for this testing should be given. The implications of this also should be considered in 4.3. For instnnce. it is essential that the responsibility is defined for ensuring that bases or screeds meet the specified standards of level, smoothness, dryness and soundness (impact crushing resistance) before any subsequent or finishing trades are called to commence work. In most circumstances. this should be the responsibility of the main contractor.
4.7 Health and safety
Arrangements for liaison and cooperation on health and safety requirements between the different parties
in the contract should he established.
4.8 Responsibilities
Responsibilities for cleaning the construction on completion and giving it initial protection should be
defined.
4.9 Maintenance
The customer should be left with adequate details of the maintenance required to enable the floor covering to perform satisfactorily in use. The recommendations should include details of the various types of cleaning and maintenance needed and the time scales at which they should be carried out. It is preferable that such instructions should be in clear, written form and cover the recommended maintenance methods appropriate for all the types of floor coverings installed.
5 Sub-floors
5.1 General
The appearance and performance of the floor coverings covered by this British Standard are determined to a large extent by the quality of the prepared base or screed.
Those responsible for the design and construction of the subfloor should ensure that it meets the requirements, i.e. should ensure that it has the necessary characteristics to allow the floor covering to be installed successfully before the installer of the floor covering is asked to commence work.
These characteristics include:
a) regularity of concrete floors and screeds;
b) moisture content of concrete floors and screed. (These should be determined using the test method given in Annex A);
c) integrity of screeds;
d) cracks made good;
e) construction joints treated;
0 gaps and changes of level;
g) moisture content of wooden subfloors;
h) presence of asbestos in an existing floor covering.
5.2 Materials
5.2.1 Fabricated substrates
Fabricated substrates may be selected from the lollowing:
a) plywood:
h) particle board (the hoard should not have any surface treatment which might affect adhesion);
c) oriented strand board (OSB)
d) fibreboard (e.g. hardboard, MDF);
e) gypsum board;
f)  others.
The strength and construction of the fabricated substrate should be able to function in use without swelling. delaminating or disintegration.
5.2.2 Cementitious based substrates (let’elling layer)
A levelling layer is used where a conventional sandkement screed is considered unsuitable because of thickness or other limitations.
The levelling layer may be a cementitious underlay consisting of a specifically formulated blend of cement and binder and both fine and coarse aggregates. The binder is commonly a natural rubber latex or synthetic polymer.
5.2.3 Anhyd rite screed
After it has been laid, it is essential that the surface is sanded to remove laitance. It is essential to provide a barrier primer before cement based products are laid over the anhydrite and it is preferable to prime where flooring adhesives are to be applied. The screed manufacturer should be contacted for advice regarding primers.
5.2.4 Underlayments
Underlayments may be selected from the following:
a) cementitious underlayment consisting of a specially formulated blend of cement, binder and fine aggregate. The binder is commonly a natural rubber or synthetic polymer dispersion;
b) powder/water mixes based on casein/cement or polymer/cement and fine aggregate;
c) epoxy or other resin compounds (e.g. primer);
d) compatible underlayments that are available for direct contact with an anhydrite screed.BS 8425 pdf download.Code of practice for installation of laminate floor coverings