Garden Room Construction

Timber Stud Sizes

The stud size depends on:

• wall height

• structural loads

• insulation thickness

• roof design

• glazing openings
   

The frame should not simply be copied from a garden shed if the room is intended for year round occupation.

 

Structural Sheathing

Structural sheathing adds stiffness to the timber frame.
 

Common materials can include:

• OSB

• plywood

• proprietary structural boards
   

The sheathing helps resist racking and ties the wall frame together.

 

Vapour Control

A vapour control layer helps reduce moisture moving from the warm interior into colder parts of the structure.
 

This is especially important in insulated buildings.
 

Poor vapour control can lead to condensation within the wall or roof.

 

Breathable Membrane

A breathable membrane is generally positioned towards the outside of the insulated frame.
 

Its role is to help protect the structure from external moisture while allowing water vapour to escape.

 

Ventilated Cavity

Many cladding systems benefit from a ventilated cavity behind the outer finish.
 

This allows moisture to drain and air to circulate.
 

The cavity also helps separate the cladding from the weather resistant layer behind.

 

External Cladding

Possible cladding materials include:

• cedar

• larch

• thermowood

• composite

• fibre cement

• metal

• painted timber
   

The choice affects:

• appearance

• maintenance

• cost

• durability
  
   

Garden Room Roof Construction

The roof needs to deal with:

• structural loads

• rainwater

• insulation

• condensation

• drainage

• roof covering
   

Flat roofs are particularly common on contemporary garden rooms.
 

Garden Room Flat Roof Construction

A typical flat roof may include:

• internal ceiling

• vapour control layer

• roof joists

• insulation

• roof deck

• waterproof membrane
   

Depending on the design, the roof may be formed as a warm roof or another suitable insulated arrangement.

 

Warm Roof Construction

A warm roof generally positions the principal insulation above the structural deck.
 

This helps keep the roof structure warmer and can reduce condensation risk when detailed correctly.
 

It may also provide a very clean technical solution for a garden room.

 

Roof Falls

A flat roof should not actually be completely flat.
 

It needs sufficient fall to drain rainwater towards:

• gutter

• outlet

• downpipe
   

The fall should be designed rather than improvised during construction.

 

Roof Coverings

Common garden room roof finishes include:

• EPDM

• GRP

• single ply membrane

• metal roofing

• standing seam

• green roof systems
   

The chosen covering needs to suit the roof construction and expected lifespan.

 

Garden Room Ceiling Construction

The ceiling can be finished with:

• plasterboard

• timber lining

• acoustic panels

• decorative boards
   

The ceiling also provides an opportunity to incorporate:

• recessed lighting

• speakers

• ventilation

• data

• access panels
  
   

Doors and Windows

Glazing is one of the biggest visual features of a garden room.

Options include:

• fixed glazing

• French doors

• sliding doors

• bifolding doors

• corner glazing

• rooflights
   

The structural frame needs to be designed around these openings.

 

Large Glazed Openings

Large openings may require:

• beams

• lintels

• additional studs

• engineered timber

• steelwork
   

This should be resolved before the frame is built.

 

Garden Room Insulation

A year round garden room should normally consider insulation to:

• floor

• walls

• roof
   

Good insulation reduces heat loss and helps improve comfort.
 

It should be coordinated with:

• airtightness

• ventilation

• glazing

• heating
  
   

Electrical Construction

Most modern garden rooms need electricity.
 

The electrical design may include:

• sockets

• lighting

• heating

• data

• external lighting

• air conditioning

• kitchen equipment
   

The routes should be planned before the internal walls are closed.

 

Service Zone

A service void can be useful inside the wall.
 

This can allow cables to be installed without repeatedly cutting through the vapour control layer.
 

It also makes future alterations easier.

 

Plumbing

 

If the garden room includes:

• WC

• shower

• sink

• kitchen

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the water and drainage routes should be planned early.

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Trying to add plumbing after the floor and walls are complete can create unnecessary work.

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Garden Room Construction Sequence

 

A typical build might follow this order:

1. Set out the building

2. Install foundations

3. Construct floor

4. Erect wall frames

5. Install roof structure

6. Sheath the frame

7. Weatherproof the building

8. Install doors and windows

9. Install services

10. Fit insulation

11. Complete internal lining

12. Install cladding

13. Finish electrics and heating

14. Decorate

15. Install final flooring

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The sequence can vary, but having a plan prevents trades getting in each other's way.

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Weatherproof the Building Early

 

One of the key objectives during construction is to get the building weather tight.

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Once the roof, membranes, doors and windows are in place, the interior can be completed with much less risk from rain.

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Construction Tolerances

 

Garden room construction still needs accuracy.

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Poor setting out can result in:

• doors not fitting

• windows out of square

• uneven cladding

• roof drainage problems

• internal finishes looking poor

​

Checking levels, dimensions and diagonals throughout the build is important.

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Build Your Own Garden Office

 

Homeowners comfortable with DIY may choose to undertake parts of the project themselves.

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Possible DIY tasks include:

• timber framing

• insulation

• cladding

• decorating

• flooring

• landscaping

​

Specialist work can still be carried out by appropriate contractors.

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Use Local Trades

 

You do not need a national garden room company to build a good garden room.

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With proper drawings, you can obtain prices from:

• local carpenters

• builders

• electricians

• plumbers

• groundworkers

• roofers

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That can give you far more control over the final cost.

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One Builder or Separate Trades?

 

There are two main approaches.

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One Main Builder

One contractor manages the entire build.

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Advantages include:

• simpler communication

• one point of responsibility

• easier programme management

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Separate Trades

You appoint each trade individually.

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This can potentially save money but requires more homeowner involvement.

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Garden Office Construction Cost

 

The cost depends on:

• size

• foundation

• structure

• glazing

• insulation

• cladding

• electrics

• heating

• finishes

• labour

​

Managing the project yourself can reduce some of the contractor overhead and margin.

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DIY Versus Turnkey

 

A turnkey garden room is convenient.

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But convenience has a cost.

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The supplier may need to cover:

• sales

• marketing

• surveying

• project management

• administration

• subcontractors

• overhead

• profit

​

A self managed project allows you to decide how much of that process you want to take on yourself.

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Design Before You Build

 

One of the most common mistakes is starting construction before the details are resolved.

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Before work starts, decide:

• dimensions

• foundation

• floor build up

• wall construction

• roof construction

• insulation

• cladding

• glazing

• electrics

• heating

• drainage

​

Making those decisions on paper is far cheaper than changing them on site.

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Garden Room Construction Plans

 

Proper construction plans can show:

• setting out

• foundation arrangement

• floor build up

• wall construction

• roof construction

• insulation

• structural openings

• doors and windows

• key junctions

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That gives builders a clear basis for pricing and construction.

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APN Garden Room Plan Packs

 

This is exactly where the APN model works.

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You start with a professionally designed garden room and use the plan pack to organise the build.

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You can then:

• build it yourself

• use a local builder

• employ separate trades

• source your own materials

• compare quotations

• choose your own finishes

• control the final specification

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Where additional information is required, APN can also provide:

• design adaptations

• Building Regulations information

• structural coordination

• foundation details

• specialist construction details

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Potential Savings of 40 to 50%

 

Depending on the design, location, specification and how the project is managed, it may be possible to reduce the overall cost by around 40 to 50% compared with some equivalent turnkey garden room packages.

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The aim is not to build a cheaper room.

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It is to spend more of your budget on the room itself and less on the layers surrounding it.

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That could mean:

• better glazing

• better insulation

• better cladding

• better internal finishes

• a larger room

• more money left for landscaping or furniture

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Start With the Design

 

The first step is choosing the right garden room.

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From there, you can:

• use the design as shown

• adapt it to suit your garden

• obtain planning advice if required

• add Building Regulations information where needed

• request builder quotations

• source products and materials

• control the final build cost

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Choose the design. Control the build. Keep more of the budget.

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Browse Our Garden Room Designs

Explore the APN Garden Rooms collections and find the design that works for your space, your lifestyle and your budget.

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