Roofs

Question 1

What is a ‘cold roof’?

Answer 1

Thermal insulation is located between theceilingjoists meaning that everything above the insulation, such as the rafters, and anyroofspace, will be colder than the living space below it.

Question 2

What is a ‘warm roof’?

Answer 2

The insulation layer is laid on top ofroofstructure.

Question 3

Name 8 terms used to describe the various parts of a pitched roof?

Answer 3

1. Valley
2. Ridge
3. Hip
4. Hipped End
5. Roof slope
6. Verge
7. Gable end
8. Eaves

Question 4

What do firming pieces create?

Answer 4

A sloping surface on a roof

Question 5

What two things can firming consist of?

Answer 5

1. Tapered lengths of fir (softwood) nailed to the top of each joist
2. Varying depth lengths of softwood nailed across the joists

Question 6

How do we ensure that frames resist racking or falling over?

Answer 6

By utilising cross bracing, gable end walls for bracing, whipped ends for bracing

Question 7

Hip tiles are nailed to what?

Answer 7

The hip rafter

Question 8

What is the typical width for lead Valley gutters?

Answer 8

125mm

Question 9

Tiling battens are typically what size?

Answer 9

38 x 25mm

Question 10

Slates are typically nailed to what size of batten?

Answer 10

50x25mm

Question 11

Roofing felt is laid under what?

Answer 11

Timber battens

Question 12

Ridge tiles are usually bedded in what?

Answer 12

Mortar

Question 13

A low-pitched roof is typically between what two degrees to the horizontal?

Answer 13

10 and 30 degrees

Question 14

The principal coverings for low pitched roofs are what?

Answer 14

Copper and aluminium strips 450 or 600mm wide (both of which are comparatively light in weight and therefore do not require heavy timbers to support them).

Question 15

Can copper and aluminium sheets be bent without damage to the material?

Answer 15

Yes

Question 16

In timber roof construction the insulation boards are nailed directly to the rafters. The counter battens over the roofing felt (DPM) and insulation is fixed how?

Answer 16

By nailing through the insulation to the rafters.

Question 17

A roof is defined as flat when its weather plain is finished at a slope of what degrees?

Answer 17

Between 1 and 5

Question 18

In a flat roof, timber joists are generally spaced at what centres?

Answer 18

400 to 600mm centres

Question 19

What is rough boarding?

Answer 19

When boards are left rough surfaced from the saw

Question 20

In sheet metalwork the word dressed describes what?

Answer 20

The shaping of the sheet

Question 21

Where the lead flat roof is surrounded on all sides by parapet walls, where do we collect the rainwater?

Answer 21

At the lowest point on the roof

Question 22

What is a wood roll in a lead flat roof?

Answer 22

A Wood Roll is used to provide a watertight expansion joint between two separate sheets of Lead.

Question 23

The usual thickness of copper sheet for roofing is what?

Answer 23

0.6mm

Question 24

The standard size of sheet for copper roofing are what two sizes (L x W)?

Answer 24

1. 1200 x 900mm2. 1800 x 900mm

Question 25

The minimum fall for a copper covered roof is what?

Answer 25

1 in 60 ( firming pieces used to create fall)

Question 26

What is the cheapest metal used for roofs?

Answer 26

Zinc

Question 27

Name two materials that have been used as a waterproof membrane for timber framed roofs?

Answer 27

1. Asphalt - as a continuous membrane

2. Bitumen felt - laid in layers to form a membrane or skin.

Question 28

Bitumen felt is generally used on what type of roofing?

Answer 28

Flat