How To Work Out The Gauge On A Slate Roof

As a guide a slate of 500 x 250 sizes uses a slate and half of 500 x 375.

How to work out the gauge on a slate roof. The best place being 3 5mm as this gives the best resistance to wind uplift so for our example we will work with 4mm although it can be as high as. The gauge is in fact the same as the margin which is the length of the slate exposed. For a 500mm long slate with a 100mm headlap the gauge is 500 100 400 2 200 so we know the gauge is 200mm. This calculator will estimate the following number of slates required per square metre.

The holing gauge can be calculated as. The supplier of the slates should recommend the spacing up the roof between the battens known as the gauge this usually varies according to the size of the slates the pitch of the roof and the degree of exposure. You can assess this in two ways either as the roof pitch angles which the rafters make with the horizontal or the proportion between the run and the rise of the roof. Measure the distance from the top of the lowest batten to the top of the highest batten.

Divide the distance by the maximum gauge of the tiles being used and round the result up to the next largest whole number. Slate length mm battening gauge mm m batten per m2. Batten gauge length of slate headlap 2. Holing gauge mm battening gauge mm m batten per m2.

Height of slate minus desired headlap divided by two gauge i e. You would need 2 5 of these slate per linear metre. Total linear run of tile batten in metres. Finally divide the measured distance between the battens by the rounded number you now have the gauge that your roof requires.

Therefore if your rafter length was 4 linear meters your calculation would be 4 x 2 5 10 quantity slate half s. The result is the number of courses of tile on the roof rounded to a whole number. Often you express roof pitch as the ratio between the rise and the run in the form of x 12. Holing gauge mm battening gauge mm m batten per m2.

Roof pitch refers to the slope which the rafter creates. Now we can work out the holing gauge with gauge headlap x. Holing gauge batten gauge headlap 10mm. Holing gauge for holing slates.

X the nail hole clearance so that a nail does not strike the top of the slate underneath. Rounded up this becomes 13 then divide this into the original measurement 246 15mm. Tile batten gauge for slate.