All of our Cotswold Summerhouses are made in our works by our Carpenters. We do not 'buy-in' any of our timber buildings, and that allows us to ensure exceptional quality buildings are constructed only using the best quality materials and craftsmanship. With over 35yrs experience in timber building manufacture, we have managed to identify the key areas where many of our 'competitors' fail to provide the 'extras' needed to ensure your timber building will last for years.

Cotswold Summerhouse Specification

  • Height to Apex- 2.350m external, internal 2.220m
  • Height at eves- 2.120m external, internal 1.990m
  • Overhang canopy- 900mm x width of the summerhouse
  • Decking with handrail- 900mm x width of the summerhouse
  •  Building size is the floor base dimension in metres equivalent to imperial building size, excluding the 900mm deck and veranda. Example 2.4m equivalent to 8ft. If you choose to have the optional deck and overhang canopy please add 900mm to the overall length.


  • Frame material-  ex. 50 x 75mm CLS Tanalised timbers, uprights at a maximum of 400mm centres.
  • The framework is clad with Novia Ultra breathable waterproof lining sheeting before cladding installation. Novia Ultra lining sheeting allows moist air to pass from inside the building out through the lining but stops moisture from penetrating from the outside.
  • The external cladding is Ex. 16mm x 125mm Tanalised  Redwood rebated shiplap - no one else uses the shiplap cladding we do as our shiplap is machined specifically for HAYMAC with an extra deep 13mm rebate to stop shrinkage inside the rebate and tongue joint causing problems. A black plastic weatherstrip is fitted beneath the bottom shiplap board to shed water away from the building floor base frame.
  • 15mm thick Tanalised external corner weathering fillets.


  • Full framed floor framework using ex. 50  x 75mm CLS  Tanalised timbers with bearers at 300mm centres.
  • The floor deck is 15mm OSB 3 (moisture resistant) floorboard sheeting. Many of our competitors use the same boards on the floor as they do on the external cladding. OSB 3 sheet flooring does not shrink, collect dirt in the joints and is much stronger. 
  • Do not let anyone suggest OSB3 sheeting is inferior to individual TGV boards as is is not, we have been building timber buildings for over 35 years and know what is best! OSB3 is used in the construction industry in houses for walls and roof decks, so it must be good enough for any garden outbuilding?


  • Roof bearers are ex. 50  x 75mm CLS Tanalised  timbers at 400mm centres.
  • A roof truss installed at maximum 6ft intervals along the length of the building to avoid roof 'sagging.'
  • The roof deck is 11mm OSB 3 (moisture resistant). An OSB 3 roof deck is superior to individual roof boards as the roof joints do not shrink which is the main cause of roof felt failure, as when the timber joint shrinks it puts stress on the roofing felt, causing it to crack. Do not let anyone suggest OSB3 sheeting is inferior to individual TGV boards as is is not, we have been building timber buildings for over 35 years and know what is best! OSB3 is used in the construction industry in houses for roof decks so it must be good enough for a garden building!
  • The roof deck is covered with high strength, with an exceptional anti-tear property, Polyester based green mineral coated roof felt.
  •  Our roofing felt should not be confused with standard roof felt which tears very easily used by nearly all other timber building manufacturers as standard who only offer our roofing felt as an optional upgrade at extra cost.
  • 15mm thick Tanalised prepared bargeboards and fascias with soffit boards fitted to the gable ends
  • The fascia boards are designed with a drip bar at the top for the roofing felt to lip over, allowing easy installation of guttering.
  • Standard front over hang is 165mm.
  • Deck and veranda option will extend the canopy overhang to 900mm.

Windows and Doors

  • Windows are made using a full-frame and window cill with 4mm clear float glass. Option to upgrade to opening windows. Non-opening windows are 600 wide x 900mm deep.
  • The paired doors are fully framed ledged and braced with a door cill fitted to the bottom of the door opening frame which the door shuts on. The doors are half glazed with 4mm clear float glass panels each 400mm wide x 920mm high. The door opening provides for a clear opening of 1145mm wide x 1755mm high.
  • The door is clad using ex. 19x125mm  Tanalised TGV and is hung using 12" medium weight black Tee hinges with a black press key lock and 2 brass barrel bolts to keep one door closed at all times and 2x turn buttons.

Timber Treatment

  • All of our Cotswold Summerhouses use fully Tanalised pressure treated timber for the framework, cladding, bargeboards, fascias, floor bearers and corner weathering fillets. Tanalised timber provides effective protection against timber rot but is not water repellent and as such we recommend you treat the external timbers of your building using a suitable weatherproofing exterior grade paint. Please view our product care sheet on weatherproofing & painting for more information.

                                                                              NO OTHER TIMBER BUILDING MANUFACTURER OFFERS OUR SPECIFICATION AS STANDARD AT OUR PRICES!