Recommended laying and fixing specifications for Coverland concrete roof tiles.

The following laying and fixing specifications for Coverland concrete roof tiles have been established in accordance with SANS 062/1956 (Code of Practice for fixing concrete roof tiles), SANS 0160/1980 (Code of Practice for the general procedures and loadings to be adopted for the design of buildings), BS 5534 - Part 1/1978 (Code of Practice for slating and tiling and design), MONIER Roofing technology data, and extensive experience gained by MONIER Roofing.

Roofs in exposed and coastal areas can experience severe wind lifting forces. In these situations special recommendations for additional mechanical fixings apply. The principal factors to be considered in deciding on the necessity for additional fixing are:

1. The exposure of the site.

2. The height above ground of the roof.

3. The pitch of the roof.

4. The higher wind loadings encountered at eaves and verges.

5. Environmental influences.

Mechanical Fixing
Cupola	100 mm long nail/clipped
Clay Tile	50 mm long nail/clipped
Double Room	63 mm long nail/clipped
Elite	50 mm long nail/clipped
Taunus	75 mm long nail/clipped
Rake Verge	75 mm long nail
Tile Clips	50 mm long nail
Tile Clips for Elite	25 mm long nail

 Specific laying and fixing specifications for these locations must be considered for each situation.

 

DEFINITIONS

RAFTER PITCH

The angle of elevation between the horizontal plane and the angle of the rafter. Roof pitch = rafter pitch

TILE PITCH

The angle of elevation between horizontal and the tile when laid.

Note: The tile pitch has a lower angle of elevation than the rafter pitch.

Low roof pitch 17° to 25°.
Normal roof pitch 26° to 35°.
High roof pitch 36° and above.

LAYING SPECIFICATIONS

HEADLAPS

The minimum headlap for Coverland concrete roof tiles is 100mm on 17°-25° and 75mm on pitches of 26° and above. All Coverland concrete roof tiles, with the exception of the Elite, should be laid "straight-bond".

MECHANICAL FIXING

Coastal regions (up to 30km inland):
Aluminium alloy/Non-corrodible serrated clouthead nails of the correct length to suit the profile.

INLAND REGIONS:

Electroplated serrated clouthead nails of the correct length to suit the profile. Non-corrodible "stormclips" should always be used where specified. Ensure correct stormclip is used for specific profiles.

FIXING SPECIFICATIONS

The following fixing guide should provide a sound functional roof in each of the defined exposure categories. However, it cannot encompass all possible circumstances, or the unanticipated worse than the "once in 50 years" prediction. Special laying and fixing specifications must be considered for each situation where the roof pitch, height of the roof, exposure of the site and/or environmental influence are unknown, in doubt, or felt to be critical. Please refer to MONIER Roofing for advice in these circumstances.

CATEGORY A - UNEXPOSED AREAS

All inland regions other than certain specified areas.

CATEGORY B - SEMI-EXPOSED AREAS

Coastal regions and certain inland areas. Generally the area within 30km from the coastline, the top of the escarpment or the watershed of the first mountain inland. Whilst cognizance should be taken of local practices, the application of good roofing practice should not be compromised for expediency.

CATEGORY C - EXPOSED AREAS

Critical coastal areas, and certain inland areas. The classification of exposure categories assumes the use of a suitable underlay, properly fixed over the total area of the roof including the gable end and eave overhangs. When possible, local knowledge and local wind speed data should be used in the assessment of the exposure category. (Refer to SANS 0160/1980 for Regional Basic Design Wind Speed determination.)

FIXING GUIDE

CATEGORY A - UNEXPOSED AREAS

All inland regions other than certain specified areas. Mechanically fix two courses of tiles at the eaves, ridge and verges for the full overhang, whichever is greater. Cut tiles at hips, valleys and abutments to be secured with kro clips or coverfill. It is recommended that closed soffits be fitted on all verge and eave overhangs.

Roof pitches

17° to < 26° - undertile membrane mandatory.
26° to < 45° - undertile membrane recommended.
45° to < 55° - undertile membrane recommended, each tile to be nailed.
55° to vertical - undertile membrane mandatory, each tile to be nailed and clipped.

CATEGORY B - SEMI-EXPOSED AREAS

Coastal regions and certain inland areas. Mechanically fix a band of tiles (x) equal to a fifth of the number of courses on the rafter lengths at the eaves and ridges, and also at chimneys and abutments. Mechanically fix a band of tiles equal to (x) along (y), as calculated above, at each verge (or the full overhang, whichever is the greater.) Tiles at hips, valleys and abutments to be secured with kro clips to every third tile on the roof. Closed soffits must be fitted to all verge and eave overhangs.

Roof pitches

17° to < 26° - undertile membrane mandatory.
26° to < 45° - undertile membrane recommended (mandatory at the coast).
45° to vertical - undertile membrane mandatory, each tile to be nailed and clipped.

CATEGORY C - EXPOSED AREAS

Critical coastal areas and certain inland areas. Roof pitches

17° to < 26° - undertile membrane mandatory, each tile to be clipped.
26° to < 45° - undertile membrane mandatory, each tile to be nailed or clipped.
45° to vertical - undertile membrane mandatory, each tile to be nailed and clipped.
Closed soffits to be fitted at all verge and eave overhangs.

The exposure category of the required roof may be assessed using the following table:

Height to Ridge not exeeding M	Regional Basic Design Wind Speed ms-¹	Exposure Category
5	41 to 40 and below 41 to 49 inclusive 41 to 50 and above	A B C
10	44 to 43 and below 44 to 49 inclusive 44 to 50 and above	A B C
15	43 to 42 and below 43 to 47 inclusive 43 to 48 and above	A B C