Gillies & Mackay Radiata Garden Room Conditional Guarantee

Your Gillies & Mackay Radiata Garden Room is guaranteed for 30 years. 

Of course, we didn’t just pluck this number from the air. We can offer you this guarantee with complete confidence because we’ve seen firsthand how our buildings perform. We’ve been building Garden Rooms, Garages and Sheds since 1989, and with the right care, those early buildings are still standing firm all these years on. 

Every decision we make contributes to the durability of our buildings and the quality of our workmanship. We choose the best materials for the job, selecting the best-quality timber for our cladding and framing. Where appropriate we use pressure-treated and thermally-treated wood that is incredibly resistant to water, rot and insects. 

We put all our experience, knowledge and expertise into producing 30-year buildings, and then it’s over to you. We promise to uphold the terms of the Guarantee, and you promise to care for your building. But don’t worry – you’re not on your own! Our Aftercare Guide has all the information you need to ensure that your building endures and surpasses the guarantee period. The combination of our craftsmanship and your care is what makes a Gillies & Mackay building last a lifetime. 

Here’s everything you need to know:


This Guarantee is valid for 30 years from your delivery date, subject to the conditions outlined below. It applies to your Radiata Garden Room and covers defects in materials and workmanship. 

During the 3-month settling-in period remedial adjustments may be required, typically doors/windows or defects unidentified in our quality control processes.

Under the terms of this Guarantee, any defects relating to workmanship will be remediated and any failed components replaced.

You may return your building within 14 days of delivery, after which you will be refunded the cost of your building minus the deposit. Gillies & Mackay are not liable for any costs relating to groundwork or electrics for a returned building. 

In the event of any unresolvable ongoing recorded dissatisfaction, the returns period is extended to 6 months, after which a refund minus the deposit will be issued. 

Outwith these 6 months, a compensation refund will be issued at a discretionary amount calculated on usage and the age of the building upon return.


General Maintenance

The Garden Room’s structural integrity and resistance to moisture and rot are maintained through the innovative Radiata ThermoWood cladding. 

Your building is delivered with a coat of Osmo oil. No recoating is necessary unless you wish to retain the original finish. To retain this finish reapply a coat of Osmo oil according to the manufacturer’s guidelines. The natural weathering to a silvery grey colour of uncoated cladding is normal and not a defect.


If you wish to paint your Radiata Garden Room, you must use Sadolin Classic. Incorrect application or use of non-recommended products will void this guarantee.


Steel box profile and Isola shingle roofing materials are guaranteed by their manufacturers for 20 and 30 years respectively. This guarantee does not supersede the manufacturer’s guarantees, which must be adhered to.


If installed, guttering should be checked and cleaned at least twice a year, and more frequently if trees overhang your building. Failure to maintain the guttering can lead to water damage, which is not covered under this guarantee.


For laminate flooring, avoid using wet mops and opt for disposable floor wipes to prevent moisture buildup. Excess moisture damage to flooring due to improper care is not covered by this guarantee.


Adequate ventilation is required to protect the timber inside the Garden Room, especially after any liquid spills. A lack of ventilation that leads to moisture accumulation inside the room is not covered by this guarantee.

Doors and Windows

Natural timber frame movement over time is normal and is not considered a defect. If adjustments are necessary due to excessive movement, this must be done by a qualified carpenter at the owner’s expense.


This guarantee does not cover damage due to improper use, unauthorised alterations, natural disasters, normal wear and tear, natural fading of materials, or superficial damage.

This guarantee does not cover Issues arising from non-compliance with the aftercare instructions provided in the Gillies & Mackay Radiata Garden Room Aftercare Guide.


All claims under this guarantee must be made with proof of maintenance compliance, including receipts for materials used and records of maintenance activities.

This guarantee ensures that the product is maintained as intended, protecting the integrity and longevity of your Radiata Garden Room while providing clarity on the responsibilities and expectations for care. If you need additional details or modifications to this draft, please let us know by contacting