Detailed Specification

Please note: all imperial measurements are approximate and Mercia garden buildings are made from metric measurements.

Product Name: 12 x 8 (3.80m x 2.43m) Mercia Garden Room Summerhouse with Side Shed
Footprint (Front Width x Depth): 3.80m x 2.43m (12'5" x 7'11") including side shed
Side Shed is 890mm (2'11") wide)
Height To Ridge: 2.14m (7'0")
Height To Eaves: 2.05m (6'9")
Walls: 12mm Shiplap Tongue and Groove
Door (s) Concertina Double Doors
Solid Single Side door
Door(s) Height x Width: 1.7m x 1.80m (5'7" x 6'0")
1.7m x 0.6m   (5'7" x 1'11")
Lock: Press Lock
Roof: 12mm Shiplap Tongue and Groove
Roofing Felt: Green Mineral
Floor: 12mm Shiplap Tongue and Groove
Bearers: 27mm x 44mm (1" x 2")
Bearers Direction: Left to Right
Window(s): 2 x Styrene Clear Glazed
Framing 28mm x 44mm (1" x 2")
Portabases Available: N/A
Eco Bases Available: N/A
Number Required: N/A
Manufacturers Guarantee: 10 Year Anti-Rot Warranty
FSC Certified: Yes
Free Delivery: Yes
Assembly Available: Yes
EAN Number: 5029442076560
Manufacturer: Mercia




A combi summerhouse and side shed which offers the best of both worlds at an affordable price.

The 12 x 8 Mercia Garden Room Summerhouse with Side Shed comes with a side shed, so you get a handy storage shed as well as a fantastic wooden summerhouse.

The Mercia summerhouse-shed hybrid combines all the best elements of a contempory summerhouse with the practicality of a garden shed. With the concertina doors slid open you get a full view out into your garden making it perfect for relaxing during the summer months. Or with the summerhouse doors secured it's perfect for storage throughout the British winter, the built in side shed also ensures that extra storage is available making this summerhouse a welcome addition to your garden all year round!

You can assemble the Side Shed on either the right-hand side (as shown in the picture) or the left-hand side.

Walls - The walls of the summerhouse are constructed from high quality, FSC certified timber. It uses specially designed tongue and groove cladding to give you a summerhouse that is not just durable but also a summerhouse that looks great in your garden. Also our planed tongue and groove shiplap cladding design closes the pores and together with its curved profile promotes the run off of water making the summerhouse more water resistant.

Doors - The concertina summerhouse doors are fully styrene glazed and as with the walls are constructed from high quality FSC certified timber.

Roof And Floor - The roof and floor of the summerhouse are constructed from high quality tongue and groove cladding, this makes summerhouse more water resistant. The summerhouse floor also comes with high quality floor joists giving the summerhouse a solid sturdy feel and greater load capacity.

Windows - All summerhouse windows are glazed with environmentally friendly styrene which is a safer alternative to traditional glass, this allows plenty of light to flood into the summerhouse.

Full assembly instructions are provided with the summerhouse and with all the fittings in the box as standard you will be amazed at how simple your summerhouse is to install.

Please note All our summerhouses are pre-treated with a water based timber treatment for protection during transit. In order to receive the full 10 year anti-rot guarantee on your summerhouse, it is necessary that you treat the summerhouse with a high quality, water-based, timber preservative prior to or shortly after construction. This will protect the timber from weathering on your summerhouse and will need to be repeated accordingly in relation to manufacturer's instructions. This summerhouse is shown painted in one of the photos for decorative purposes. However this summerhouse is supplied unpainted and with the veranda as optional.

Please note: The image shows the 12' x 8' Summerhouse with side shed on the right-hand side. 

The Summerhouse also comes in a 10' x 8' Please click here



Key Features

  • The Side Shed's Intelligent Design allows you to choose whether you would like to assemble it on the right or left at the time of assembly
  • Delivered Flat-Packed With Instructions, Fittings and Sand Mineral Roofing Felt
  • Tongue and Groove Shiplap Wall and Door Construction. 
  • Concertina Doors are Fully Glazed to let Light Flood Into the Summerhouse
  • Tongue and Groove Roof and Floor
  • Two Fixed Styrene Clear Glazed Windows
  • Built in Side Shed as Standard
  • 10 Year Anti Rot Warranty
  • FSC Certified.


ALL DELIVERIES ARE DELIVERED TO KERBSIDE OR DRIVEWAY. All of our Mercia products are delivered flat packed other than fence panels (which are delivered fully constructed), direct to your home, and are supplied with a set of instructions to support assembly.

Booking Delivery

You will be required to book your delivery date at the time of placing your order (except for Metal Shed). Our 'Request a Delivery Date' service is available to the majority of areas and you'll find that the majority of the UK postcodes are FREE but some areas may incur a delivery surcharge and some postcodes are not covered at all. Select a 'requested delivery date' by entering your postcode in the 'Request a delivery date' section above. You will also be notified at this time if your area incurs a surcharge or delivery is not covered in your area.

Prior to Delivery

On the morning of your delivery date, you'll be sent an update by text with an estimated 2-hour delivery slot (this update can only be provided where a mobile number has been supplied on the billing address section at the time of checkout) together with a link to the manufacturer delivery portal where you'll be able to track your order.

Please note: Mercia Metal Sheds ONLY - your order is delivered by a courier you will not be notified prior to the delivery. If you are not in on the day of the delivery you will be carded and asked to contact the courier to arrange a new mutual delivery date. The estimated delivery lead time for Mercia's Metal sheds is identified on the product for the metal shed. Lead times are on working days (Monday - Friday) excludes Bank Holidays. These estimated lead times are provided by the manufacturer. Some remote areas will take a little longer.

Upon Delivery

Your order is delivered either kerbside or driveway and will be delivered on either a 3.5T, 7.5T or 18T Lorry. Unfortunately due to health and safety and insurance liabilities the driver will not be able to take your goods around to the back of your property but may upon request place the product at the side of the house if there are no access or restriction issues. We would not risk damaging your property whilst delivering a product to an unsafe location. Unfortunately, we will not be able to go through your property.

We would recommend against arranging for a third party to install the building before it's been delivered and checked that all parts are present, as we cannot be held liable for any third-party costs.


Orders with Assembly 

The lead time for our installation option is around 12 weeks from the date of order. With the installation option, the majority of orders will have their delivery and installation on separate days; there will be a small number of orders which will have delivery and installation on the same day. You will be advised by the manufacturer's installation team which category your order falls into.

Depending on the installation option for your order, you will be contacted within the delivery timescale and given a date for either delivery/assembly on the same date or a separate date for delivery and assembly.

12 x 8 (3.80m x 2.40m) Mercia Garden Room Summerhouse with Side Shed

Was £2299.99 Now £1,799.99
NEW - Guarantee - 10 year - gold

Product code - 20040122


Description Information

The 12 x 8 Mercia Garden Room Summerhouse comes with a built in side shed, so you get a handy storage shed as well as a fantastic wooden summerhouse.

  • Built in Side Shed can be assembled on either the left-hand side or right-hand side
  • Tongue and Groove construction throughout
  • 10 Year Anti-Rot Guarantee

View full specification Delivery

Usually delivered: Use Pick A Day delivery below for your earliest delivery date to your Post Code.

Note: Currently not available for delivery to Offshore Post Codes.

excludes installation option
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  • 12ft x 8ft (approx) Mercia Garden Room Summerhouse with Side Shed£1,799.99