Nearly 1 million buildings sold 
10-year guarantee 
Free Delivery *to most of uk 
uk manufactured BillyOh Petra Tongue and Groove Reverse Apex Summerhouse
The Petra is a bright building with windows across the front and double side windows. The tall windows and doors are glazed with shatter-resistant SAN giving you fantastic views and natural light without the worry of glass. With only one side having windows, it couldn’t be easier to place your Petra to the side of a garden or patio, making it a fantastic corner summerhouse. Due to the natural light and views given by the windowed front wall, the Petra has many uses and would work great as a home office, summerhouse bar, garden studio or decorate it with all your home accessories to create a relaxing home away from home.
All of the Petra summerhouse sizes come with 11mm Tongue and Groove roofing and flooring as standard. Not only does this building come with a robust floor and roof included, but the reverse apex design offers increased head height and lends itself to an everyday use office or relaxation room. Apex and reverse apex roof styles are typical in more traditional summerhouses and offer excellent water runoff. Roofing felt is also included to improve your building’s weather resistance helping to keep your possessions safe and dry.
This BillyOh building comes in a selection of sizes from 10x8 to 20x10. Our wide range of base sizes for the Petra reverse apex summerhouse is designed to be suitable for all types of gardens and budgets. The smaller 10x8 could fit perfectly onto a patio space or at the bottom of a garden giving you great space to sit no matter the weather. The larger sizes offer more space for bigger furniture sets which can be great for hosting or a family room.
Adaptable Configuration
The movable panels allow you to move the doors and windows any where you want along the front of the building to best suit your garden and leave you in complete control of creating your perfect summerhouse.
Extra Tall Apex Roof Design
The generous height design gives you enough space and freedom to easily move around. With a tall ridge height of 7'8" to 8'1", depending on the size, and eaves height of 5'8", the extra head height and room is ideal for when you are hosting get togethers, parties and other events with friends and family.
High Quality Construction
For added strength and stability, all of our garden buildings feature double framed corners and have 28mm x 28mm floor joists to provide a sturdy base to support your summerhouse.
Shatterproof Glazing
The tall, durable single SAN glazing improves the structural strength of the building while giving you fantastic views of your garden and natural lighting.
Durable T&G Construction
Constructed using strong and durable 11mm Tongue & Groove cladding, the panels interlock with each other to provide your summerhouse building with a tight seal protection against the weather.
Floor and Roof Included
The Petra summerhouse is supplied with heavy-duty 11mm Tongue & Groove flooring and roofing as standard to provide a solid underfoot for your garden building and protection from harsh weather conditions.
Wide Opening Double Doors
The wide opening double doors are perfect to open up when you are relaxing with friends and family. With an opening size of 3'9" x 5'4", the wide doors also provide easy in and out access to your summerhouse and ensure you can move larger items or furniture around with ease.
Roofing Felt Included
As standard this garden room is supplied with mineral roofing felt, this added protection ensures your garden building is offered the ultimate protection and longevity against harsh weather conditions
Delivery & Assembly
We offer FREE delivery to most postcodes.
Our buildings are delivered in easy to assemble panels. For your convenience the panels are no wider than 4ft so they can be easily manoeuvrable and fit through a standard doorway.
We do not offer an installation service on any of our buildings, our buildings are designed and made to be easy and simple to assemble. Using the assembly instruction included in your order confirmation and with a team of at least 2 people you can expect to have your BillyOh building up within a day, or as little as 3-4 hours with some of our smaller buildings.
| Dimensions | 10 x 8 | 12 x 8 | 12 x 10 | 16 x 8 | 16 x 10 | 20 x 10 |
|---|---|---|---|---|---|---|
| Width | 299.6cm | 358.2cm | 358.2cm | 475.4cm | 475.4cm | 592.6cm |
| Depth | 259.8cm | 259.8cm | 318.3cm | 259.8cm | 318.3cm | 318.3cm |
| Width (Internal) | 287.4cm | 346cm | 346cm | 463.2cm | 463.2cm | 580.4cm |
| Depth (Internal) | 234.4cm | 234.4cm | 293cm | 234.4cm | 293cm | 293cm |
| Eaves Height (Inc Floor) | 173.2cm | 173.2cm | 173.2cm | 173.2cm | 173.2cm | 173.2cm |
| Eaves Height (Internal) | 175.4cm | 175.4cm | 175.4cm | 175.4cm | 175.4cm | 175.4cm |
| Ridge Height (Internal) | 229.3cm | 229.3cm | 242.4cm | 229.3cm | 242.4cm | 242.4cm |
| Ridge Height (Inc Floor) | 234cm | 234cm | 247cm | 234cm | 247cm | 247cm |
| Door Opening Size (w x h) | 114.8cm x 163.9cm | 114.8cm x 163.9cm | 114.8cm x 163.9cm | 114.8cm x 163.9cm | 114.8cm x 163.9cm | 114.8cm x 163.9cm |
| Door Height | 164.5cm | 164.5cm | 164.5cm | 164.5cm | 164.5cm | 164.5cm |
| Door Width | 58.3cm | 58.3cm | 58.3cm | 58.3cm | 58.3cm | 58.3cm |
| Minimum Base Width | 300cm | 358cm | 358cm | 476cm | 476cm | 593cm |
| Minimum Base Length | 260cm | 260cm | 319cm | 260cm | 319cm | 319cm |
| Roof Material | 11mm Tongue and Groove | 11mm Tongue and Groove | 11mm Tongue and Groove | 11mm Tongue and Groove | 11mm Tongue and Groove | 11mm Tongue and Groove |
| Floor Material | 11mm Tongue and Groove | 11mm Tongue and Groove | 11mm Tongue and Groove | 11mm Tongue and Groove | 11mm Tongue and Groove | 11mm Tongue and Groove |
| Roof Covering Material | Green Mineral Felt | Green Mineral Felt | Green Mineral Felt | Green Mineral Felt | Green Mineral Felt | Green Mineral Felt |
| Glazing Material | Styrene | Styrene | Styrene | Styrene | Styrene | Styrene |
| Glazing Thickness | 0.18cm | 0.18cm | 0.18cm | 0.18cm | 0.18cm | 0.18cm |
| Cladding Style | Tongue and Groove | Tongue and Groove | Tongue and Groove | Tongue and Groove | Tongue and Groove | Tongue and Groove |
| Windows | 6 windows (all fixed) | 6 windows (all fixed) | 6 windows (all fixed) | 8 windows (all fixed) | 8 windows (all fixed) | 10 windows (all fixed) |
| Factory Basecoat Treatment | Optional - Dip Treated or Pressure Treated | Optional - Dip Treated or Pressure Treated | Optional - Dip Treated or Pressure Treated | Optional - Dip Treated or Pressure Treated | Optional - Dip Treated or Pressure Treated | Optional - Dip Treated or Pressure Treated |
| Locking System | Turn Button | Turn Button | Turn Button | Turn Button | Turn Button | Turn Button |
| Pre-Assembled Side Panels | Yes | Yes | Yes | Yes | Yes | Yes |
Spray Treated: Our sheds and summerhouses get a beautiful golden brown spray treatment before leaving the factory in order to preserve the quality of the wood up until the delivery. As this only lasts through the transit stage, we do advise treating the wood after installation to protect and preserve it, as well as annual maintenance.
Pressure Treated: For an extra level of protection, you can opt for a pressure treated building which is an effective way of keeping the wood long lasting. This is an extra step in the manufacturing process where the wood is treated in a pressurised tank. Chemical preservatives are forced deep into the wood’s fibres to resist rot, decay and termites. When you upgrade to Pressure Treatment, the guarantee is extended from 10 to 15 years.
All garden buildings should be assembled on a firm and level base. A base will ensure your building has a solid, long-lasting and well-drained foundation.
If you want to build your own base, from a sturdy material such as concrete or flagstones, you can find minimum dimensions for each size of this building in the tech specs. In order to protect your building from moisture, you should leave a 2ft gap around the exterior of your building, so remember to take this into consideration when laying any sort of base.
Our robust and simple to use EcoBase provides you with a firm, long-lasting foundation with suitable drainage for your garden building. It is quick and easy to install through the use of snap connectors that link the grids to each other.
The building should be treated once fully assembled and within one month of receiving the product. Always consult the directions on the treatment that you have purchased.
Delivery Once your order is placed we endeavour to send out an acknowledgement email, providing you with the applicable contact details as provided to us, your order reference number and estimated delivery date. In most cases, you will be contacted prior to that estimated delivery date to notify you the day in which your delivery will be made.
Payment At BillyOh we do manufacture our buildings to order, therefore immediate payment is required for this item. To make the process easy we want our customers to have as many options as possible, we accept most major credit and debit cards and PayPal payments.
Returns If you're not 100% happy with your new purchase, you can return it within 14 days of delivery. We also ask you if you can send a photo just so we can confirm everything looks okay before we send our drivers to collect the item. For any requests, issues and concerns, please do not hesitate to contact us.
