Costs: Doorsets and site assembled doors

Doorsets versus site assembly

Doorsets comprise the complete door assembly including the door frame, door leaf or leaves, ironmongery and accessories. Doorsets incur higher material costs than

site-assembled doors but reduced installation times. Typical installation time for a fully furnished and finished doorset is two to three hours. Fitting a similar door in situ and installing equivalent ironmongery, accessories, glazing and decoration may add four to seven hours so the complete installed capital cost of a doorset may be less than an equivalent site-assembled door.

Factory-controlled manufacture of doorsets should reduce the risk of defects associated with inaccurate installation. As a fully assembled domestic front door may comprise 30-80 individual items, which need to be measured, cut and fixed, there is scope for errors that in the life of the door are likely to require additional maintenance intervention or result in premature failure.

Where door installation is straightforward or for refurbishment of old properties with non-standard openings, site assembly may be the preferred option.

Whole-life performance and cost issues

First ensure the doorset meets key functional requirements such as fire protection, security, weather tightness and sound insulation. And second, assess component options with reference to expected use, failure modes and durability requirements.

Fire doorsets

Fire doors should be specified with third-party certification assuring performance for the required period of fire protection to BS 476-22 or BS EN 1634. Ensure the certificate covers the actual model of door specified. BS 8214 gives guidance for non–metallic fire doors.

Design and installation issues

Specification of a fire-rated doorset avoids the potential pitfalls of site assembly including ensuring the ironmongery, edge gaps and seals are compatible and achieve the required fire resistance under the design ventilation conditions either side of the door.

Where fire doors are expected to perform a smoke-controlling function, ensure the edge seal system specified is suitable for the door type and expected usage. Choose edge seals that have been tested for performance, preferably 100,000 opening and closing cycles.

BD DD 171 classifies doors by strength and durability based on four duty categories: light, medium, heavy or severe. Enhanced security may be achieved using PAS 23 and PAS 24, which test for operating forces, weather exposure categories and loads in use, abusive forces on handles, a cyclical test as well as various impact loads.

External exposure suitability should be confirmed by BS EN 12207 for air permeability, BS EN 12208 for watertightness and BS EN 12210 for wind load resistance.

Ironmongery

Ironmongery should be specified using the classes in the European standards to match component performance with expected usage. The standard for single axis hinges BS EN 1935 has four categories of use: light, medium, heavy and severe duty. It has eight durability grades according to the number of test cycles the hinge can endure. Specify door closers to at least power grade three in BS EN 1154. Locks and latches should comply with standards BS 5872 category A for housing and category B for buildings requiring a more robust construction.

Maintaining integrity of fire doors

The importance of inspecting and maintaining fire doors in use cannot be overestimated. Regular inspection of the door should confirm correct functioning and adequacy of condition. Smoke seals and moving parts should be cleaned and ironmongery with moving parts lubricated every six months. Worn components should be replaced.

Doorset material

There is no perfect material solution for doorsets.

Each material offers a compromise between functionality, durability, use in practice and the service environment.

Timber doorsets may warp, shrink, expand or distort due to moisture changes. External doorsets are more at risk, but damage can be controlled by regular decoration.

Plastics, glass and reinforced plastics doorsets may discolour due to the effects of ultraviolet light. Impact damage may result in the complete door requiring replacement, as repairs may not be feasible.

Mild steel-based doorsets are prone to indentation from severe impacts, which are not easily repaired. External mild steel doorsets require regular decoration to prevent corrosion.