Grandmaster | Affordable Pressure Treated Garden Sheds
10% off the Grandmaster range with code GM10 Offer ends in 8d: 16h: 10m: 03s

Grandmaster

The Grandmaster range is Project Timber’s flagship collection of heavy duty pressure treated garden buildings, designed and manufactured in Britain. Whether you need a spacious garden workshop, a classic summerhouse or a versatile…

25 products
Grandmaster "Heavy Duty" D1000 Workshop Shed - Pressure Treated Tongue and Groove
10% offCode GM10

Grandmaster "Heavy Duty" D1000 Workshop Shed - Pressure Treated Tongue and Groove

From £1,549 £1,394
36 sizes: from 8ft × 8ft to 24ft × 14ft
 Current promotion
Grandmaster Diplomat "Classic" G1000 Summerhouse - 11mm Pressure Treated Tongue and Groove
10% offCode GM10

Grandmaster Diplomat "Classic" G1000 Summerhouse - 11mm Pressure Treated Tongue and Groove

From £1,631 £1,468
35 sizes: from 8ft × 8ft to 24ft × 14ft
Grandmaster "Heavy Duty" D1000 Apex Workshop Shed - Pressure Treated Tongue and Groove
10% offCode GM10

Grandmaster "Heavy Duty" D1000 Apex Workshop Shed - Pressure Treated Tongue and Groove

From £1,549 £1,394
36 sizes: from 8ft × 8ft to 24ft × 14ft
Grandmaster "Heavy Duty" D1000 Apex Workshop Windowless Shed - Pressure Treated Tongue and Groove
10% offCode GM10

Grandmaster "Heavy Duty" D1000 Apex Workshop Windowless Shed - Pressure Treated Tongue and Groove

From £1,549 £1,394
36 sizes: from 8ft × 8ft to 24ft × 14ft
Grandmaster Clubhouse G1000 Summerhouse - 11mm Pressure Treated Tongue and Groove (8ft Internal Depth)
10% offCode GM10

Grandmaster Clubhouse G1000 Summerhouse - 11mm Pressure Treated Tongue and Groove (8ft Internal Depth)

From £1,549 £1,394
5 sizes: from 8ft × 10ft to 24ft × 10ft
Grandmaster "Heavy Duty" D1000 Pent Shed - Pressure Treated Tongue and Groove (8ft Internal Depth)
10% offCode GM10

Grandmaster "Heavy Duty" D1000 Pent Shed - Pressure Treated Tongue and Groove (8ft Internal Depth)

From £1,699 £1,529
5 sizes: from 12ft × 10ft to 20ft × 10ft
Grandmaster Clubhouse Storeroom G1000 Summerhouse - 11mm Pressure Treated Tongue and Groove (8ft Internal Depth)
10% offCode GM10

Grandmaster Clubhouse Storeroom G1000 Summerhouse - 11mm Pressure Treated Tongue and Groove (8ft Internal Depth)

From £2,499 £2,249
7 sizes: from 12ft × 10ft to 24ft × 10ft
Grandmaster Diplomat "Classic" G1000 Summerhouse - Offset Door - 11mm Pressure Treated Tongue and Groove
10% offCode GM10

Grandmaster Diplomat "Classic" G1000 Summerhouse - Offset Door - 11mm Pressure Treated Tongue and Groove

From £1,631 £1,468
35 sizes: from 8ft × 8ft to 24ft × 14ft
Grandmaster Clockhouse Classic G1000 Summerhouse - 11mm Pressure Treated Tongue and Groove
10% offCode GM10

Grandmaster Clockhouse Classic G1000 Summerhouse - 11mm Pressure Treated Tongue and Groove

From £1,999 £1,799
27 sizes: from 8ft × 10ft to 24ft × 14ft
Grandmaster "Heavy Duty" D1000 Workshop Windowless Shed - Pressure Treated Tongue and Groove
10% offCode GM10

Grandmaster "Heavy Duty" D1000 Workshop Windowless Shed - Pressure Treated Tongue and Groove

From £1,549 £1,394
36 sizes: from 8ft × 8ft to 24ft × 14ft
Grandmaster "Heavy Duty" D1000 Workshop Shed – Offset Door – Pressure Treated Tongue and Groove
10% offCode GM10

Grandmaster "Heavy Duty" D1000 Workshop Shed – Offset Door – Pressure Treated Tongue and Groove

From £1,549 £1,394
36 sizes: from 8ft × 8ft to 24ft × 14ft
Grandmaster "Heavy Duty" D1000 Workshop Windowless Shed - Offset Door - Pressure Treated Tongue and Groove
10% offCode GM10

Grandmaster "Heavy Duty" D1000 Workshop Windowless Shed - Offset Door - Pressure Treated Tongue and Groove

From £1,549 £1,394
35 sizes: from 8ft × 8ft to 24ft × 14ft
Grandmaster Fusion "Classic" G1000 Summerhouse with Side Shed - 11mm Pressure Treated Tongue and Groove
10% offCode GM10

Grandmaster Fusion "Classic" G1000 Summerhouse with Side Shed - 11mm Pressure Treated Tongue and Groove

From £2,127 £1,914
25 sizes: from 12ft × 8ft to 24ft × 14ft
Grandmaster Lounge "Contemporary" G1000 Garden Room - 11mm Pressure Treated Tongue and Groove (8ft Internal Depth)
10% offCode GM10

Grandmaster Lounge "Contemporary" G1000 Garden Room - 11mm Pressure Treated Tongue and Groove (8ft Internal Depth)

From £2,225 £2,002
4 sizes: from 10ft × 10ft to 22ft × 10ft
Grandmaster Diplomat "Classic" G1000 Summerhouse - Long Window - 11mm Pressure Treated Tongue and Groove
10% offCode GM10

Grandmaster Diplomat "Classic" G1000 Summerhouse - Long Window - 11mm Pressure Treated Tongue and Groove

From £1,681 £1,513
36 sizes: from 8ft × 8ft to 24ft × 14ft
Grandmaster "Heavy Duty" D1000 Workshop - with Side Door - Pressure Treated Tongue and Groove
10% offCode GM10

Grandmaster "Heavy Duty" D1000 Workshop - with Side Door - Pressure Treated Tongue and Groove

From £1,649 £1,484
36 sizes: from 8ft × 8ft to 24ft × 14ft
Grandmaster Duke "Classic" G1000 Summerhouse - 11mm Pressure Treated Tongue and Groove
10% offCode GM10

Grandmaster Duke "Classic" G1000 Summerhouse - 11mm Pressure Treated Tongue and Groove

From £1,861 £1,675
11 sizes: from 8ft × 10ft to 20ft × 12ft
Grandmaster Fusion D1000 Pent Dual Room – Pressure Treated Tongue and Groove (8ft Internal Depth)
10% offCode GM10

Grandmaster Fusion D1000 Pent Dual Room – Pressure Treated Tongue and Groove (8ft Internal Depth)

From £2,120 £1,908
5 sizes: from 12ft × 10ft to 20ft × 10ft
Grandmaster Heavy Duty D1000 Pent Shed Windowless - Pressure Treated Tongue and Groove (8ft Internal Depth)
10% offCode GM10

Grandmaster Heavy Duty D1000 Pent Shed Windowless - Pressure Treated Tongue and Groove (8ft Internal Depth)

From £1,699 £1,529
5 sizes: from 12ft × 10ft to 20ft × 10ft
Grandmaster "Heavy Duty" D1000 Workshop Windowless - with Side Door - Pressure Treated Tongue and Groove
10% offCode GM10

Grandmaster "Heavy Duty" D1000 Workshop Windowless - with Side Door - Pressure Treated Tongue and Groove

From £1,649 £1,484
36 sizes: from 8ft × 8ft to 24ft × 14ft
Grandmaster Alpine G1000 Summerhouse Cabin - 11mm Pressure Treated Tongue and Groove
10% offCode GM10

Grandmaster Alpine G1000 Summerhouse Cabin - 11mm Pressure Treated Tongue and Groove

From £4,956 £4,460
8 sizes: from 16ft × 9ft to 20ft × 16ft
Grandmaster Alpine G1000 Summerhouse Cabin - Plain Side - 11mm Pressure Treated Tongue and Groove
10% offCode GM10

Grandmaster Alpine G1000 Summerhouse Cabin - Plain Side - 11mm Pressure Treated Tongue and Groove

From £4,956 £4,460
8 sizes: from 16ft × 9ft to 20ft × 16ft
Grandmaster "Reverse Apex" D1000 Workshop - 11mm Pressure Treated Tongue and Groove
10% offCode GM10

Grandmaster "Reverse Apex" D1000 Workshop - 11mm Pressure Treated Tongue and Groove

From £1,039 £935
12 sizes: from 8ft × 8ft to 20ft × 12ft
Grandmaster Alpine G1000 Summerhouse Cabin - Long Windows - 11mm Pressure Treated Tongue and Groove
10% offCode GM10

Grandmaster Alpine G1000 Summerhouse Cabin - Long Windows - 11mm Pressure Treated Tongue and Groove

From £5,107 £4,596
8 sizes: from 16ft × 9ft to 20ft × 16ft
Grandmaster Diplomat Pavilion G1000 Summerhouse - 11mm Pressure Treated Tongue and Groove
10% offCode GM10

Grandmaster Diplomat Pavilion G1000 Summerhouse - 11mm Pressure Treated Tongue and Groove

From £9,607 £8,646
7 sizes: from 12ft × 16ft to 20ft × 16ft
Showing all 25 products

Grandmaster

The Grandmaster range is Project Timber’s flagship collection of heavy duty pressure treated garden buildings, designed and manufactured in Britain. Whether you need a spacious garden workshop, a classic summerhouse or a versatile garden room, every Grandmaster building combines robust construction with affordable pricing — without compromising on quality.

Choose from over 25 designs across the Grandmaster, D1000 and Alpine ranges, available in sizes from a compact 8×8 shed up to expansive 24×14 workshops. Options include apex, reverse apex and pent roof styles, double or French doors, windowed or windowless designs, and dual-room layouts for combined storage and workspace.

Every building is constructed from pressure treated tongue and groove cladding (11mm as standard, with a 16mm upgrade available on selected models). The interlocking shiplap boards lock out wind and rain, while pressure treatment forces preservative deep into the timber — the most effective protection against rot, decay and wood-boring insects. That’s why every Grandmaster building is backed by a 15-year anti-rot guarantee, with no annual re-treatment required.

Each Grandmaster comes complete with quality floor, roof and all fixings included as standard. No experience? No problem — every building is supplied with clear, step-by-step assembly instructions, making installation straightforward for any DIYer. With free delivery to most UK mainland postcodes and flexible finance options available, your ideal garden building is closer than you think.

Made in Britain Free delivery (selected postcodes)* Up to 25-year anti-rot guarantee*