# Green Oak Timber Frame Garden Room

By Murray MacArthur

Topic: Home & DIY

[Open the interactive Jig](https://ask.jig.com/j/gX0yDx6d6Cyu)

## Guide

### 1. A room made of oak

This garden room stands on a skeleton of solid oak beams, with glass between them\. You get to choose its size, roof, base and doors\. Drag the garden to walk around it\.

Scroll or pinch to move closer\.

### 2. Green means fresh

Here is the bare frame\. "Green" oak is not green in colour: it is freshly cut and still full of sap, so it is soft enough to carve\. Beams this thick would take years to dry, so builders use them fresh\.

Fresh oak can be more than 30% water by weight\.

### 3. Pegs, not nails

Each joint is a tongue of wood, called a tenon, fitted into a slot, called a mortice\. Dry oak pegs, glowing here, are hammered through holes drilled slightly out of line, which pulls the joint tight\. Ordinary steel nails would stain the oak black\.

The braces curving up to each beam stop the frame from leaning\.

### 4. Choose a size

Oak frames are planned in bays: the space between two pairs of posts\. Each bay here is 1\.95 metres long, so adding one stretches the room without changing its width\. Try two, three or four bays\.

Two bays make about 15 square metres; four bays about 30\.

### 5. Choose a roof

A gable roof has two slopes and a triangle at each end\. A hipped roof slopes on all four sides, a lean\-to slopes one way, and a flat roof can carry a glass lantern to let in sky\.

Clay tiles or slate suit a sloping roof; a flat roof needs a waterproof sheet\.

### 6. Choose a base

The oak should not sit in wet ground, so the frame stands on a low wall or a stone floor\. A dwarf wall of brick or stone, about knee high, makes the room feel snug\. Glass to the floor brings the garden right inside\.

This dwarf wall is 450 millimetres tall\.

### 7. Doors to the garden

French doors open the room to the garden\. Other popular choices are sliding doors or folding doors that stack to one side\. Open these and step out onto the doorstep\.

### 8. Oak keeps changing

Green oak dries in place for a year or two\. As it dries it shrinks across the grain and small cracks called shakes appear\. They are normal, and the joints get tighter\. Outside, the honey colour slowly weathers to silver grey\.

A 150 millimetre post can shrink by about 6 millimetres across its width\.

### 9. Before you build

Check the rules where you live\. In England, a garden building within 2 metres of a boundary can usually be no taller than 2\.5 metres, shown by the glowing sheet\. Taller roofs need to stand further back\.

Oak garden rooms are often 15 to 35 square metres\.