The Larch Observatory

For the Larch Observatory, we adopted a reductionist approach to design at the request of the owner: simplicity would be key, with minimal external features, clean lines, perfect symmetry and even the roofline to be simplified with a level, square frame disguising the required slope.

We chose Siberian Larch for its unique properties: known as the ‘tree of eternity’ it has long been prized for its longevity – its high resin content ensuring a life commensurate with many hardwoods. It also possesses an aesthetic beauty beyond that of more common species – it has a unique warmth of appearance, frequent small knots and a lovely natural honey colour. From a technical point-of-view, its natural moisture resistance ensures that rainwater is repelled rather than attracted to the structure.

As an upgrade to the design of our The Hillside Observatory, which was also clad in Siberian Larch, we were able to use specially-commissioned 6″ glue-laminated larch beams to form the frame of this observatory, giving it a chunky, sturdier appearance and providing the necessary strength to support the structure over its large 3m x 3m footprint: as usual, our suspended floor design provides complete isolation from the central telescope pier, whilst keeping the observatory free from moisture.

Internally, the observatory is finished in moisture-resistant MDF, which has been painted matt black to ensure an absence of internal reflections, creating the ideal environment for high-end astro-photography. Specially sourced matt black electrical faceplates, red and white LED lighting, and a corner desk complete the interior.

The almost-flat roof of the observatory is uniquely constructed with a purlin design, ensuring the slope runs toward the North side, and it rolls on no less than twelve top-quality sealed ball-bearing stainless v-groove wheels. Despite its considerable weight, it can be smoothly and easily opened with just one hand.

The entrance door is our standard solid hardwood-faced fire door for security, but is this time clad in matching Siberian larch, carefully planned to ensure the joints line up with the cladding around the door for a seamless appearance.

painted interior

Available as an option, our fully painted interior maximises your experience. We will paint the observatory matt black internally to minimise reflections, and the warm room can be painted in your choice of colour to enhance comfort in daytime use. If you opt for the painted interior, we upgrade the internal wall lining from 11mm OSB to 12mm moisture-resistant MDF.

Siberian Larch

Siberian Larch (Larix Sibirica) grows natively from the Finnish border eastwards to central Siberia in Russia and is a frost-hardy species capable of surviving in freezing temperatures. As a result it grows very slowly and this gives it some wonderful properties – it is dense and resinous, which gives it extraordinary longevity, and also utterly beautiful.little light as you wish. Building them into the walls means no bulky fittings or obstructions, maximising the space in your observatory.


Our ‘flat’ roof (it has a slight angle to allow rainwater to drain off) is covered with a single-piece EPDM rubber membrane. The lack of any joints means there’s no leaks, and the tough rubber membrane resists damage by impact or weathering, resulting in an expected 50-year lifespan. Where appropriate, we’ll fit a gutter on the low side to channel water away safely to the ground.

Overall Size (mm):3190 (L) x 3190 (W) x 2452 (H)
 Observatory Size (Internal, mm):2890 (L) x 2890 (W) x 1850 (H)
 Warm Room Size (Internal, mm):Not included
 Total length including frame (mm):6439
 Roof type:Flat roof
 Exterior Cladding:Siberian Larch vertical channel cladding
 Interior Wall Lining:Painted moisture-resistant MDF
 Roof Covering:One-piece EPDM rubber membrane
 Roof Pitch:<1 Degree
 Additional Features:Framed roof hides EPDM trims for consistent appearance
Siberian larch glulam frame
Location:South East England, UK
Completed:December 2016
Approximate Project Cost*:£9,900

* Approximate project cost does not include VAT, haulage, groundworks, telescope or pier, and represents what a similar project might cost if completed now, including any improvements to our base specification.