For Architects and Builders

If you are writing a gun room specification for a private house, this page has the four things you actually need: our scope, the builder’s works we depend on, where the licensing conversation sits in the programme, and how we sit inside a main contract.

A meaningful part of our work arrives through architects, interior designers and main contractors. We are used to being one trade among thirty on a large house, to arriving after the decorator without causing an argument, and to being asked for a revision at four o’clock on a Friday.

Our scope

That division is deliberate rather than a limitation. Your contractor is on site, holds the programme and carries the structural risk. A joinery workshop arriving from Suffolk to form an opening would be the most expensive way available of doing something your groundworker can do on a Tuesday.

Builder’s works we depend on

Give us these and the installation is clean. Miss one and it is not.

Item	Note
Structural opening formed, lintel in, frame ready to receive	Firearms door and frame are heavy; the opening must be square and sound
Wall substrate suitable for anchoring	Masonry preferred. Timber frame needs studs, noggins and backing located and recorded
Floor level, and load checked	A full gun room is heavy — steel, timber, glass, cartridges
First-fix electrics to agreed positions	Cabinet and rack lighting, door switch. Final connection by your electrician
Ventilation strategy resolved	Steel-lined rooms are cold rooms. See below — this is the detail most often left out
Room dry, plastered and decorated where visible	We install into a finished shell, not a wet one
Access route confirmed	Doorways, turns and stairs. Access defeats more installations than size does

Ventilation, specifically

A steel-lined room with no air movement is where blued steel goes to rust, and the client will notice within one winter. Resolve the ventilation or dehumidification strategy with your M&E consultant at design stage; we will make sure our joinery does not obstruct it, and we ventilate cabinet interiors as a matter of course. Gentle background heat and stable humidity beat a warm room every time.

Siting the room on the plan

Where the gun room goes is a design decision worth making early, and it is usually made late — the room ends up wherever is left over once the good rooms have been allocated. A few principles, offered as things to weigh rather than rules:

• Internal is better than external. A room with no external wall has no external attack face and no window to argue about. Where an external wall is unavoidable, masonry is a great deal easier to work with than timber frame.
• Away from the obvious. A room reached through the main body of the house, rather than off a rear lobby or straight off an attached garage, is a longer and noisier route for anybody who should not be there.
• Windows are a complication, not a disqualification. If the room has one, expect the licensing conversation to include it, and design accordingly.
• Discretion is part of the specification. A room labelled on the drawings as the gun room will be known as the gun room by every trade on site and by everyone who ever sees the plans. Consider what it is called on the drawing.
• Think about the route in from the field. The best gun rooms sit near the boot room and the back door, not at the far end of a carpeted hall.
• Head height and door swings. Gun cabinets are tall and the doors are heavy. A room that works in plan can fail in section.

Where a client wants concealment rather than discretion, that has to be designed in at plan stage — a hidden entrance built into joinery is a very different drawing from a clad door in an opening, and it usually needs a little more space than the client expects.

Coordination with other consultants

Three interfaces come up on nearly every project, and each is cheap to resolve early and expensive to resolve late.

With	What needs settling
Structural engineer	Wall substrate and floor loading. A fully loaded gun room is heavy, and the fixings need something real to go into
M&E consultant	Ventilation or dehumidification, background heat, and lighting circuits with a door switch
Security consultant or alarm company	Detection within the room, and whether cabling routes clash with the steel lining. Steel and wireless devices are not always friends

On the last point: agree cable routes before the lining goes on. Chasing a route through a steel-lined and clad wall afterwards is possible, and it is nobody’s favourite afternoon.

Programme, and the one item that trips it

Our lead time runs from approved drawings, not from appointment. A single cabinet is typically a matter of weeks; a fitted room is longer, and a room with concealment and matched joinery can run to several months. We give you a date and we hold it — on-time delivery is what our contractor clients come back for.

The item that trips programmes is the licensing conversation. The client’s specification should be agreed with their firearms enquiry officer at design stage. It has no dependency on site progress whatsoever, and yet it is routinely left until practical completion, which is the single most expensive moment available to discover that a licensing department would like something different.

We handle that conversation. What we need from you at the outset is simply which force licenses the client, and the exact wording of any conditions on their certificate. The FEO process is set out in full here.

Drawings and issue

• 3D CAD, with elevations, plans, sections and context renders.
• Issued into your set, in your format, at your revision points, with your title block conventions where you want them used.
• Comments taken directly from you or the interior designer, rather than relayed through the client.
• Coordination drawings where we cross services, structure or another trade’s work.
• Record drawings as installed, issued with the specification sheet at handover.

We survey ourselves before manufacture, always, including where a full set of architect’s drawings exists. That is not scepticism about the drawing — it is that a piece of joinery this heavy has no tolerance for a wall being out of square at one end, and the survey is far cheaper than the remake.

Writing the specification

If you are drafting an NBS clause or a schedule item, this is the substance of what we build to. It can be copied and it can be tendered against.

• Enclosure: 3mm (0.12in) steel throughout, formed and reinforced corners
• Doors: folded steel with returned edges; anti-cut pins to hinge side engaging the frame
• Locking: 8-lever safe lock to EN 1300 Class A; multi-point on tall doors; independent locking per bay
• Glazing (where glazed): laminated anti-bandit glass, 21.5mm (0.85in) minimum, increased with pane height; structural glazing bars
• Ammunition: separately locked compartment with independent lock
• Fixing: mechanically anchored to masonry or located structural timber; type and centres recorded and issued
• Timber: quarter-sawn solid oak, walnut or mahogany, book-matched to pairs; or hardwood prepared for paint
• Finish: French polish, hand-oiled, hand-painted or hand-antiqued, applied in-house
• Handover: signed specification sheet stating steel thickness, glass specification, lock model, fixing type and centres

A drafting note worth having: do not write “to BS 7558”. BS 7558:1992 was withdrawn on 7 November 2025 and is no longer a maintained standard. Specify the performance you want — steel thickness, lock standard, glazing type and fixing — rather than a retired document. Storage adequacy remains a matter for the client’s licensing department, and the condition sits on the certificate holder rather than on the contract.

On site

Our own fitters, on your programme and under your site rules. We protect floors and finishes, we work clean, and we take our packaging away rather than filling your skip with it. We attend design and site meetings where they are useful and stay away where they are not.

Where a finished piece will not physically reach the room — which on older houses is common — we design it to be assembled in the room, without that being apparent afterwards. Tell us early and it is a design decision. Tell us on the day and it is a problem.

Contract and paperwork

We work under standard forms where the project requires it, and we understand what notice provisions, valuation dates and defects periods actually mean rather than treating them as an inconvenience. Insurance, method statements, risk assessments and RAMS are available on request; tell us what your principal contractor requires and it will be with you before we arrive.

Trade terms are available on application. Pricing is fixed and itemised against approved drawings — see prices for where things start and what moves them.

Five things that go wrong

1. The FEO conversation happens at completionBy far the most common, and entirely avoidable. Design stage, every time.
2. Plasterboard behind the cabinetDiscovered at installation. Establish the substrate at design stage and record it on the drawing.
3. AccessThe room is right, the piece is right, the staircase is not. Confirm the route, not just the room.
4. No ventilation strategyNobody owns it, so nobody does it, and the client finds rust in February.
5. Lighting positions agreed too lateFirst fix has gone in and the switch is on the wrong side of a door that now opens the other way.

Questions we are asked

A gun room specification against the RIBA Plan of Work

The commonest programme failure on our projects is being appointed at Stage 4 for a room whose structure was fixed at Stage 3. Setting it against the RIBA Plan of Work makes the dependencies obvious.

The gun room specification split, written out

The clearest way to avoid an argument at Stage 5 is to write the split into the specification at Stage 4. Ours reads like this, and you are welcome to lift it.

By the contractor, before we arrive: structural opening formed and lintel in; substrate walls sound, dry and true to ±5 mm over 2 m; floor level and load-bearing; power and data first-fixed to agreed positions and terminated outside the lined zone; ventilation duct or trickle provision formed; room weathertight and at working temperature for a minimum of fourteen days before installation.

By us: survey; design and production drawings; steel lining and its fixings; firearms door, frame and locking; all cabinetwork, racking and interiors; finishing; delivery; installation by our own fitters; specification sheet and handover pack.

By others, by agreement: final electrical connection and certification; decoration to surrounding surfaces; intruder alarm and its contacts; any fire-rated door required beyond ours.

Two points that recur. Timber moves — a room installed at 65% relative humidity and then dried by underfloor heating will show shrinkage gaps, so the fourteen-day acclimatisation clause is not boilerplate. And the licensing conversation is the client’s, not ours and not yours; we support it, but a firearms enquiry officer will not discuss an individual’s arrangements with a third party.