Unit 1003 Building methods and construction technology

© Pearson Education 2010 Printing and photocopying permitted

Learning Outcome 3

Know about roof construction

Unit 1003 Building methods and construction technology

© Pearson Education 2010 Printing and photocopying permitted

Flat roofs

● All roofs are either flat or pitched.

● Flat roofs have a pitch of less than 10°.

● Joists are laid then decked on top. The decking must be waterproof.

What waterproof materials could be used for flat roofs?

What would happen if there was no way to drain water from flat roofs?

Unit 1003 Building methods and construction technology

© Pearson Education 2010 Printing and photocopying permitted

Types of pitched roof

Prefabricated truss roof

● Trusses are used to spread the load of the roof. Trusses are factory-made and delivered to the site.

● Bracing is fitted to keep the trusses level and secure.

Traditional/cut roof

● Loose timbers are cut in situ to give the roof its shape and spread the load. It is more time consuming than truss roofs. The roof is finished with felt, tiles or slates.

Unit 1003 Building methods and construction technology

© Pearson Education 2010 Printing and photocopying permitted

Roof components

Describe the purpose of these roof components:

● Ridge

● Purlin

● Firrings

● Batten

● Hangers and clips

● Bracing

● Felt

● Slate and tile

● Flashings

Unit 1003 Building methods and construction technology

© Pearson Education 2010 Printing and photocopying permitted

Wall plates

● Timber plates are laid flat and bedded on mortar to bear the load of the roof.

● These run along the wall carrying the feet of trusses, rafters and ceiling joints.

● They are held in place by restraint straps along the wall to anchor the wall plates.