When does a deck need a balustrade?
In England, Approved Document K says guarding should be provided in dwellings where there is a drop of more than 600 mm, and its performance standard is guarding that prevents people falling from a height of more than 600 mm. The document applies to barriers to stairs, ramps, floors, balconies and roofs that people can use, and requirement K1 for stairs applies to access outside a building only when the access is attached to the building. It doesn’t name garden decks. Ask Building Control whether yours is covered.
Wales, Scotland and Northern Ireland have their own regulations; don’t assume the English numbers apply.
How high should the guarding be?
| Location (single-family dwellings) | Minimum height |
|---|---|
| Stairs, landings, ramps and edges of internal floors | 900 mm |
| External balconies and edges of roofs | 1,100 mm |
Guarding on a raised deck that is used like a balcony may be assessed against 1,100 mm; the document doesn’t say, so ask.
How big can the gaps be?
A 100 mm sphere must not pass through any opening. The document gives that for buildings where children under five may be present and for stair guarding, and also asks you to avoid horizontal rails that a child could climb. Our kits below use spindle gaps of 100 mm.
What about handrails on steps?
The top of a stair handrail sits 900 to 1,000 mm above the pitch line or floor. It can form the top of the guarding if the heights match, and stairs 1,000 mm wide or more need a handrail on both sides. Our steps guide has the rise and going rules.
How strong must a balustrade be?
Approved Document K doesn’t give kilonewton figures. It says guarding must resist at least the loads in BS EN 1991-1-1 with its UK National Annex and PD 6688-1-1. Ask a balustrade maker for a load statement, and don’t rely on a product page that cites no regulation.
What do balustrade kits and parts cost?
| Product | Height | Price | Notes |
|---|---|---|---|
| eDecks traditional starter kit, 1,200 mm span | 950 mm | £123.57 inc VAT | 2 newel posts, timber rails, black aluminium balusters, 100 mm gap |
| eDecks traditional infill kit, 2,400 mm span | 950 mm | £172.15 inc VAT | no newel posts; sold as a reject item, add about 10 percent for waste |
| eDecks Clearview glass set, 1,795 mm span | 970 mm | £154.93 inc VAT | seven tempered glass panels; no newel posts; not for internal stairs |
| Cladco aluminium balustrade (2022 list) | 1,050 mm handrail, 1,100 mm post | 1,000 mm section £86.40, post £48 inc VAT | powder-coated black; historic prices |
| Wickes components | n/a | rail 1,800 mm £26; 15 metal balusters £46; 7 glass balusters £110 | components, not kits; VAT not stated |
The eDecks starter kit page cites no building regulation compliance, and the three eDecks sets are 950 to 970 mm high, below the 1,100 mm figure for external balconies. BestBuilders prices installed balustrades at £60 to £150 per metre.
Which posts are structural?
Decorative deck posts such as Wickes’ 82 mm chamfered post at £25 aren’t labelled structural, and Wickes’ spruce support post (100 by 100 by 1,200 mm, UC4 treated, £12.40) is the one listed for ground contact. See supports and posts for the framing posts.
How do you choose a style?
Timber, aluminium and glass are the three on offer. Check height, spindle gap, how the posts fix to the frame and the maker’s load statement before style. If you’re lighting the deck, plan cabling before the boards go down; see decking ideas.
Questions
What height should a decking handrail be?
On stairs, Approved Document K puts the top of the handrail 900 to 1,000 mm above the pitch line or floor, and a handrail can form the top of the guarding if the heights match. Stairs 1,000 mm wide or more need a handrail on both sides.
What is a deck banister?
The rail, with its balusters, along the side of a flight of steps. It sits under the same rules as other stair guarding: 900 mm high and no gap that lets a 100 mm sphere through.
Can I buy decking balustrade kits?
Yes. eDecks sells a 1,200 mm starter kit with posts at £123.57 including VAT and a 2,400 mm infill kit at £172.15, and a glass set at £154.93. All three are 950 to 970 mm high, which is below the 1,100 mm guard height Approved Document K lists for external balconies.
Does a garden deck need a balustrade?
It depends on the drop and on whether the building regulations apply. Approved Document K applies to stairs and barriers connected with a building, and doesn't name garden decks. EnviroBuild says any balustrade on a raised deck or balcony needs to meet local building regulations for height and load. Ask your Building Control body.
What are decking rails and posts?
Rails run along the top and bottom of the balustrade. Posts are the uprights, and they come in two kinds: structural posts that support the deck, and balustrade posts that carry the rail. Cladco's 1,100 mm aluminium balustrade post is a separate part from its 100 by 100 mm framing posts.
Sources
- Approved Document K: Protection from falling, collision and impact (2013 edition)
- Traditional Decking Balustrade Starter Kit 1200mm Span - eDecks
- Traditional Balustrade Infill Kit (2400mm Span) - eDecks
- Clearview Balustrade Set (1.795m Span) - eDecks
- Cladco Decking Price List 2022
- Decking Balustrades & Posts - Wickes
- Composite Decking Design Ideas for Modern Outdoor Living - Envirobuild
- Wickes Spruce Incised Deck Support Post - 100 x 100 x 1200mm
- Decking cost UK - BestBuilders