Decking near you

The three nations set different heights, so the first question is which one you are in. England's permitted development conditions for decking are the 30cm height, the 50 per cent garden coverage shared with other extensions and outbuildings, and the bar on building forward of the principal elevation, with nothing permitted within the curtilage of a listed building.

Scotland has its own class. Under the Town and Country Planning (General Permitted Development) (Scotland) Order 1992, Class 3D covers the erection, construction, maintenance, improvement or alteration of any deck or other raised platform within the curtilage of a dwellinghouse for any purpose incidental to the enjoyment of that dwellinghouse. The floor level must not exceed 0.5 metres in height, the combined height of the deck plus anything attached to it must not exceed 2.5 metres, and in a conservation area or within the curtilage of a listed building the footprint is capped at 4 square metres.

Northern Ireland is tighter still. In the Planning (General Permitted Development) Order (Northern Ireland) 2015, the class covering the erection, construction or alteration of a deck or other raised platform within the curtilage of a dwellinghouse is not available where any part of the deck would exceed 0.3 metres above ground level. Whichever nation you are in, permitted development is a default that a listing, a designation or an earlier extension can remove, so confirm with the local planning authority before ordering timber.

Almost every decision about a decking project follows from whether the finished surface stays under the permitted development height or goes above it. A low deck laid close to the ground avoids a planning application, needs no guarding, and is mostly an exercise in ground preparation, ventilation under the boards and keeping timber away from standing water. A raised platform is a small building project: planning permission, a structure designed for its loads, guarding, steps and, in many cases, a neighbour's view of your garden becoming part of the conversation.

Sloping gardens are where this bites. A deck that is level with the back door can be 30cm above ground at the house and well over a metre at the far end, and it is the height above ground that counts, not the height at the threshold. Options at that point include stepping the deck down in sections, cutting into the slope with a retaining edge, or accepting that you are making a planning application. A contractor who measures the fall across the garden before quoting is telling you which project you actually have.

The order of work is unglamorous and decides how long the deck lasts. The ground is cleared and levelled, weed growth dealt with, and the site checked for where rainwater currently runs. Supports are set out, the frame is built with falls and joist spacing to suit the boards being used, and the surface goes down last. Ventilation under the deck matters more in a damp climate than the choice of board does: a frame that cannot dry out will fail from below while the top still looks new.

Once a deck is raised, two requirements of Schedule 1 to the Building Regulations 2010 come into view. Requirement A1 is that the building is constructed so that the combined dead, imposed and wind loads are sustained and transmitted to the ground safely and without deflection or deformation that impairs stability. Requirement K2 is that stairs, ramps, floors and balconies and any roof to which people have access shall be provided with barriers where it is necessary to protect people in or about the building from falling.

The Planning Portal's advice is to assume the building regulations apply to every deck structure requiring planning permission, and to contact the local building control body if you are unsure whether what you are proposing complies. In Scotland the equivalent question is whether the work needs a building warrant, which local authorities administer alongside completion certificates, so the conversation is with the local authority verifier rather than an English approved document. What you should not do is treat guarding as a styling decision: a balustrade that looks the part but is fixed only into decking boards is the classic failure on a raised deck.

Algae is the main enemy of British decking, and it arrives wherever the surface stays damp and shaded. A deck that drains and dries quickly needs less cleaning than one built tight to the ground in a north-facing garden. Clean off green growth before it builds up, keep gaps between boards clear of leaves and moss so water can fall through, and cut back planting that keeps a corner permanently wet.

The rest is an annual look rather than a project: check fixings that have lifted, look for dark soft patches at board ends and around posts, retreat cut ends exposed by any repair, and re-oil or re-treat timber boards on the schedule the product specifies. Steps and the area by the door are worth checking first each autumn, because that is where a slippery surface does the most harm.

LokalMatch is one way to get comparable numbers in front of you. You describe the decking job once, including the size, the fall across the garden, the height you want the surface to sit at and your postcode, and matched decking and landscaping contractors get in touch directly; they pay for the requests they receive. LokalMatch does not build the deck, does not set prices and does not vet, rank or recommend any contractor, so comparing what each quotation actually includes is your part of the job.