Tile Calculator

	MetroBond 450	MetroBond 900	MetroShake	MetroShingle
Rafter Length(m)	.370	.365	.370	.235
Roof Length(m)	1.257	1.257	1.257	1.257

1) Estimating Tiles for a Straight Gable Roof

(a) Determine the Rafter length (Fig.1), divide by factor, depending on which tile is to be used.
(b) Determine the overall length of roof (Fig. 1), divide by factor, depending on which tile is to be used.
(c) Multiply the Rafter length tiles by roof length tiles, ensuring fractional tiles are counted as whole tiles.
(d) Multiply the result by 2 when estimating both sides of the roof.

2) Estimating Tiles for Hip Roofs

(a) Treat the roof initially as straight gable, and calculate as 1(a),(b),(c),and (d).
(b) Find the hip length (Fig. 2) and using one of the formulae outlined in 4, calculate the extra tiles required. Add this to the tiles required for the body of the roof.



3) Estimating Tiles for Hip and Valley Roofs

(a) Determine the tiles required for sections (a) (b) and (c) of Fig. 3 and calculate as 1(a), (b) and (c).
(b) Add the totals of (a) (b) and (c) together and multiply by 2 for both sides
(c) Determine the total lengths of hips and valleys, and using the formulae outlined in 4, calculate the extra tiles required.
(d) Add this total to tiles already calculated to obtain total tiles required.



4) Estimating Additional Tiles
Additional tiles for hips and valleys may be estimated using one of the following formulae:
Additional tiles = Total hip and valley length in linear meters x wastage factor 0.6 x 2.15 (tiles per square metre) or
Additional tiles = Total hip and valley length in linear feet x 2 and divided by 5 (square feet per tile)
5) Estimating Accessories
When calculating accessory requirements a small allowance should be included to compensate for wastage.
(a) RIDGE / HIP CAPS: Determine the length of ridges and/or hips. Divide by the linear coverage per cap (i.e 1.2m) to calculate the number of units required.
(b) BARGE COVER: Determine the length of barge boards. Divide by the linear coverage per Box Barge cover unit (i.e 1.2m) to calculate the number of units required.
(c) BARREL CAP / V-RIDGE: Determine the total length of ridges, hips and barge boards to be covered. Divide by the linear cover per unit (i.e 370mm) to calculate number of Barrel Cap / V-Ridge required.

6) Estimating Battens for New Roofing
Provide 3 linear meters of battens per square metre of roof or provide 100 linear feet of battens per 100 square feet of roof.
7) Estimating Battens for Overlay Re-Roofing
Provide 5 linear meters of battens per square metre of roof area or Provide 150 linear feet of battens per 100 square feet of roof area.
8) Simplified Methods for Quick Estimation
Some simplified methods for estimating quantities are outlined below. These may be useful as a quick checking method to prove estimating calculation:
(a) HIP ROOFS: calculate as for a straight gable roof, and add a half tile per course for each hip and valley to allow for wastage.
(b) BARGE: one length per three courses of tiles.
(c) BATTENS:
(i) Number of tiles plus 50% equals linear meters of battens required.
(ii) Number of tiles multiplied by 5 equals linear feet of batten required.
(d) UNDERLAY:
(i) 50% of the tile quantity equals square meters of underlay required.
(ii) Number of tiles multiplied by 5 equals square feet of underlay required