Shire
Shire Mammoth Shiplap Workshop 18x12
Free delivery · 28 Days
See price and delivery at retailer →- Measured size
- 18 ft 2 in x 12 ft 11 in (5.54 x 3.94 m)
- Cladding
- Tongue and groove
- Floor
- Tongue and groove boards
- Roof covering
- Mineral felt
- Doors
- Double doors; position chosen as you build
- Guarantee
- 12 months parts
Specification
Size
| Nominal size | 18 x 12 ft |
|---|---|
| Measured size | 18 ft 2 in x 12 ft 11 in (5.54 x 3.94 m) |
| Floor area | 21.83 m² |
Walls and frame
| Cladding | Tongue and groove |
|---|---|
| Frame | 44 x 70 mm |
| Panels | Modular, each panel carries through a standard door |
Floor and roof
| Floor | Tongue and groove boards |
|---|---|
| Roof | Apex roof, tongue and groove boards |
| Roof covering | Mineral felt |
Doors, windows and security
| Doors | Double doors; position chosen as you build |
|---|
Treatment and guarantee
| Material | Wooden |
|---|---|
| Guarantee | 12 months parts |
Product codes
| Brand | Shire |
|---|---|
| Colour | Honey Brown |
| Model number (MPN) | MAMM1218DSL-1AA |
| Barcode (EAN) | 5019804313815 |
From the manufacturer's listing, checked 7 November 2026. Heights are not listed, so check them at the retailer if headroom or the 2.5 m boundary limit matters.
Ownership numbers
- Price per m²
- £150
- Base to prepare
- 5.54 x 3.94 m
- Price history
- Tracked daily
- Building Regulations
- Usually exempt
Price divided by the measured floor area
About 70 paving slabs (600 x 600 mm), or 2.18 m³ of concrete at 100 mm deep
We log this price every day from 7 Nov 2026
15 to 30 m²: at least 1 m from every boundary, or built of non-combustible material
Worked out by ShedBuilder from the measured size and today's prices. Slab and concrete figures cover the footprint only; add a margin if you want a path around it.
Build one yourself instead?
Buying ready-made is about £2,051 cheaper than the materials to build it yourself. Factory-made buildings use lighter framing and thinner boards than a self-build, so building your own makes sense if you want it heavier-duty or a custom size.
The self-build figure uses our standard specification for this type of building, priced from a full materials list: framing, floor, cladding, roof, door and fixings. It excludes tools and your time.
Price an 18 x 12 ft workshop in the builderThe base you will need
An 18 x 12 ft workshop needs a firm, level base at least 18 x 12 ft. Most guarantees depend on it. A concrete slab or paving lasts longest. A plastic grid filled with gravel is quicker, drains well and needs no concrete.
EcoBase Fastfit Shed Base 6.5x4.0m (for 20x13ft)£604.00, free deliveryView at retailer →
Protect the timber
Even pressure-treated buildings last longer with a coat of treatment every couple of years. Do the first coat before it goes up, while you can reach every board edge.
Protek Shed and Fence Stain - Black 5 Litre£23.00View at retailer →
Planning permission and Building Regulations
- Most garden buildings do not need planning permission in England and Wales if they are behind the front of the house and, with any other outbuildings, cover no more than half the garden.
- Within 2 m of a boundary the whole building, base included, must be no taller than 2.5 m. Further away, the limit is 4 m for an apex roof or 3 m for other roofs, and the eaves must stay under 2.5 m. Check the height on the product page before you order.
- At about 21.8 m², a workshop this size is exempt from Building Regulations only if it stands at least 1 m from every boundary (or is built mainly of non-combustible materials).
- A workshop for your own hobbies is incidental use. Running a business from it with customers or staff visiting may need planning permission.
Check your exact building in the builder's planning check · Planning permission guide
We earn a commission from the retailer if you buy through links on this page, at no extra cost to you. It never affects which workshops we show or how we compare them. Prices were checked on 7 November 2026 and may have changed, so check the retailer before you buy.