Last modified: January 3, 2019

Building and Setting the Roof, Trusses/Rafters

Building and Setting the Roof, Trusses/Rafters


Building and Setting the Roof, Trusses/Rafters

Building and Setting the Roof, Trusses/Rafters

Written by Garden Buildings Direct
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Are you thinking about building a shed? For example to use as a storage shed or even a barn shed? If so, then it is a good idea to make a checklist of what needs to be included in the planning. An important thing to remember is a shed could have special planning permission stipulations or rules. In the UK, planning permissions (planning consent) refers to permission required to legally build or change the use of land. A planning permissions application needs to be submitted to the local planning authority (LPA) in your area.

There are many shed roof styles to choose from; pent, gable, hip, gambrel, saltbox and others, but all have standards for planning your build. When you decide to build your own shed, choosing the right roofing system is essential, there are three important factors to consider when doing this.


The StyleWill it fit the style of the shed? Will it look appealing? Since the shed will be a standing structure for years, it is important the roof suit the shed and be attractive.



WaterproofWill it prevent the contents from getting wet and keep them dry? The right materials and construction are important.



3The BudgetWill the construction of the roof design be cost-effective for its lifecycle? What materials will be needed? Traditional felt style, wooden, or clay shingles? You may opt for a more modern green living plants roof as an attractive low-cost maintenance alternative when building shed roof. Think about the durability of the materials and when choosing them. Will you want to change out the roofing material? How often will the roofing need to be replaced to maintain it properly? With careful material selection, an economic and waterproof roof that looks beautiful is possible.


Waterproof Pitches
Roofs have three broad pitch groups, meaning the angle or slope for water runoff. Depending on the desired pitch, the right materials need to be chosen to achieve the targeted slant.

A popular misconception about water is it only flows downhill and this is not always true when it comes to a roof level. Wind gusts blow water films upwards and defy gravity forcing water in between tile overlaps and into the roof’s structure. Minimum pitch standards, for any roofing system, helps ensure water tightness. Clay tiles—hard outer shell and waterproof—on top of waterproof underlay may be a more suitable material.



The Flat Roof – Pitch 0 to 10 degrees

A flat roof has a pitch of 10 degrees or lower. The main materials option used for a shed with a flat roof is bitumen mineral felt on top of sheet metal or plywood decking. If choosing a flat roof, keep in mind this will most likely require more frequent maintenance to prevent leaking. The building industry has an old saying when it comes to flat roofs: ‘There are those that leak and those that will at some point.’ Maintenance cycle will be less common if the slant is closer to a 10 degree pitch, but it will happen sooner than if using a higher pitch.


An important thing to remember, if an insulated roof is being installed, be sure to allow for an air gap between the roof deck and the insulation for ventilation purposes. This will help prevent moisture build up and the encouragement of mould growth. In addition, it is always a good idea to follow the manufacturer’s recommendations. It is also recommended by some local Authorities to add an additional 5 degrees to the manufacturer’s minimum pitch for good measure. This helps ensure ‘water tightness’.



The Low Pitch Roof – 10 to 20 degrees

A low-pitched roof is sloped at 10 to 20 degrees and the most common materials are tiles and shingles. Extra care and caution need to be taken to use waterproof underlay when installing, and it is important to follow manufacturer recommendations.



The Pitched Roof – 20 degrees and higher

A pitched roof is sloped at 20 degrees or higher. Materials commonly used for this degree of slope come with their own important ‘rules of thumb’.



Concrete Interlocking Tiles

  • Best suited material for a 20-degree or higher pitch.
  • Heavy weighted material. For safety reasons, the supporting roof and walls strength and supportability, must be considered and included in structure planning.
  • Concrete interlocking tiles are more common on larger timber structures as opposed to smaller due to their heavy weight.

8Clay Tiles

  • General pitch is at 35 degrees minimum.
  • Hard outer shell – waterproof
  • Available in a huge range of colours, sizes, and shapes.



Whatever the materials you choose to build your shed roof with, always get the manufacturer’s datasheets for the products. These will include the roof pitch minimum to keep the shed waterproof.


Roof Structure Summary

Shed Roof Design Plans

Crane Garden Buildings – Garden shed plans.

houzz – Yard and garden shed plans.

Green Roof Training – Green roof guides.

Eco-shed – Eco-friendly garden shed roof.

Red Rose Forest – Pitched shed roof design.

Shed for Easy – How to build a shed roof over a door.

Shed Made Easy – Single pitch roof shed plans.

Shed Plan Gratis – Gable shed roof plans.

Enviromat – Green shed roof.


Shed Roofing Materials Costs

A roll of mineral roof felt comes with the standard garden shed; however, these are generally on the low end of quality with a short life expectancy—3 to 5 years, and tend to be fragile. Any amount of damage to the shed roofing may allow water in and damage the shed’s structure.


For a better choice over mineral roof felt, the next step up is felt tiles or roofing shingles —15-year life expectancy. Starting at the bottom of the roof, the tiles are laid overlapping each other by roughly 150 mm. This is repeated until the ridge is reached and ridge capping is used at the very top of the roof.


Wooden shingles – 30-year life expectancy, have a layer of underlay on the bottom and are fixed to battens.


Shed Roof Design Calculator

Roof Framing Calculations

How to Calculate a Shed Roof Rafter When There Is More Than One Roof Pitch

Metric Rafter Calculations – Hip/Valley and Jack Rafters


Shed Roof Designs Pictures

Common Roof Trusses and Other Types of Roof Trusses – With Descriptions

General Roof Trusses and Gable End Roofs

Cathedral Roof Design – With and Without Ventilation Chutes


Roof Rafters vs Trusses

Which is better, roof rafters or roof trusses? It depends on whose opinion you are listening to. Some old school framers prefer rafters, but new school framers like that trusses can be built in less time and are more cost and time effective; less time to build means fewer hours.


What are rafters? Rafters support a roof deck and are a series of sloped beams extending from the hip or ridge to the wall plate (eave or downslope). Two rafters make up a couple. Rafters are prone to collapsing if there is horizontal movement; this is known as racking.


What are trusses? Timber roof trusses are structural frames that provide support to a roof by bridging the space (known as the bay) above a room. Trusses provide longitudinal support because of the added beams used in the truss structural design.


How to Build Shed Roof Trusses

Build the Shed Trusses

How to Build Barn Style Shed Roof Trusses

Mega Shed: Building and Setting the Roof Trusses

Building Roof Truss System for Shed, Barn or Tiny House

Installing Trusses on the Shed


How to Build Shed Roof Rafters

How to Cut a Roof Rafter

How to Layout Roof Rafters

Gable Roof Pattern Rafter

Gabrel Roof Rafters – Learn How to Build a Barn Roof

Ridge and Beam Rafters

Hip Roof Pattern Rafter

Building Roof Rafters

Ridge Beam and Rafters

Building and Installing Rafters

Jack Rafters

Frame a Hip Roof, Fast and Easy


No matter what type of shed you are building—small, medium or large—well thought out planning is a must. The shed roof framing design will include the type of shed roof finish: traditional shingles, clay, wood, sheet metal or eco-living; the type of support: rafter or truss; time involved, and the cost. There are many design plans available to download and videos online to guide you. Deciding which one you want to have in your yard is the first step.

Garden Buildings Direct Resources
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