Garden gazebo - Cruck Spire

Intended Use/ The Brief

We were told, " I need a summer house. I don't like straight lines I don't like right angles. Go and look at my modernist house, (which was under construction), look at the setting and make me something I would like. I like unusual and sculptural."
This garden structureis intended to be a decorative functional feature, in a parkland setting, on the approach to the main house. It should be the first large structure to catch the eye when using the main drive. It should perform this function during daylight and in the evening.
The client needs a cool place to sit in summer. It should provide a shelter from the rain and a focus for summer events.

Design Concepts / Species Incorporated.

The main design concept was to take the essence of the traditional cruck roof frame made from 2 halves of a curved tree and apply it to a spire using four quarters of a larger one. Other concepts were:-
To use English oak from sustainably managed sources, where possible selected from the tree for: structure, boarding and even cleft shingles,

To provide a simple exposed view of natural materials inside and out,

To have both convex and concave curves in the roof,

To board the roof to enhance the visual effect on the internal space of the curves of the roof, "like an oak barrel vault, but more complex",

To gather the rafters to emphasise the spire form,

To provide a roof window/lantern to illuminate the interior structure during the day, and catch the eye at night, ventilated to provide chimney effect cooling on hot days, coloured to: enhance the sky from the inside and to match silver grey oak shingles from the outside, shaped like the roof.

To provide an adzed or 'power adzed' finish to bring out the grain whilst integrating future cracks and distortion

Technical solutions

to keep this form and function effective we provided the following solutions:

1. Bending green oak rafters to their limit.
2. Dealing with sideways bends on the crucks, which produce twist on the hips. Everything is exposed so we cut special sinuous hip rafters to allow the twist to run through to the shingles
3. Steaming and bending shingles for the convex part of the roof, to avoid unsightly 'kick up',
4. Dealing with drying shrinkage and distortion, by using: appropriate allowances, traditional joints and techniques and by using air-dried timber for the boarding.
5. Keeping the structure durable by: isolating timber from damp, allowing ventilation and specifying heartwood only on surfaces exposed to the weather.

Non-timber components essential to the design are:

A new Yorkstone flag floor,

Stainless steel feet to locate the bottom of the posts and isolate them from damp,

A stainless steel and stained glass lantern/window on the tip of the spire,

A lighting scheme to illuminate the interior of the building after dark and light the lantern with light that twinkles on windy days, a forged 'oak tendril' hides the lighting supply cable.