It is very much recommended that you use a fully qualified professional roofer for the slating of your roof. This is a job that needs to be done correctly so that your roof lasts as long as possible, there is no reason for a insufficient job. This blog post describes the process we go through when installing and laying a conventional slate roof on a property.
1.First thing that we have to take into account is the pitch or angle of the roof. This determines how much overlap or headlap is required for your slates, so we use a pitch measure and follow the slate manufacturers guide lines on exactly what overlap is required. Not only the pitch is taken into consideration, the exposure and orientation of the roof is also a factor. Does the roof get a higher than average amount of rain, moisture or wind?
2. Preparing the roof. First it needs to be decided whether we are going to use new pre-holed slates or some reclaimed “second-hand” slate, this is usually a decision made by the customer. Then the old roof needs to be stripped back and all old tiles removed. For a new roof the rafters/trusses need to be completed and made sure that there are no protruding nails, splinters or anything that will disturb the lay of the slate. The roof is now ready for the under-sarking or felt to be laid.
3. Laying the felt. There are several types of membrane that can be used but we usually use the T1 type of slate felting. Starting at the bottom of the roof the felt is laid out horizontally across the roof so that there is a slight overhang going into the gutter. This makes sure that the water and moisture finds its way straight into the plastic of your gutter. To much exposure of the felt will look bad and end up getting waterlogged and rot so we keep that to a minimum. The felt is then nailed to the rafters using a 25mm clout nail, start at one of the edges and then the felt is pulled across so that there is a small amount of sag between the rafters. This draws the water away from the rafter and down towards the gutter.
4. Positioning the Slates and Slate battens. We put down the first batten across the roof and measure up your slate overhang going into the gutter (about 2 inches). Making sure the slate holes are central we then fix the batten to the rafter, then another batten is pushed right underneath so we can lay the all important eaves slate which goes underneath the first row of slates. These slates have to be cut down to size and are usually set a few mm’s shorter than the overhanging slate. Next we lay the third batten to get the correct distance for the second row of slates and the battens get nailed into place.
5. Most roofs in the UK are double lapped which means we get a really good seal. The height of the roof is measured from just under the ridge down to the 2 row batten and we can calculate how many rows of slate we are going to need, this is absolutely vital and the gauge of each row of slates can be adjusted so that we get a perfectly symmetrical and accurate number of tiles.
6. Then all we do is lay the rest of the felt, fix down the battens at exactly the right gage and then we are ready to fix the tiles. To see exactly how the tiles are laid just watch this video
For a roof replacement quote in Plymouth please visit our Roofers Plymouth homepage