CALCULATING THE "REACH"
When retrofit snow guards are used on existing roofs, they are typically installed without removing any slates or tiles. There are two basic types: notched shank snowguards that slip under the shingle and hook on an existing nail, and top hook snowguards that slide up between two slates and hook on the head of the underlying slate.
The notched shank snowguards have a limited "reach" however, and if your nails are too high, you won't be able to reach them to hook the snowguard into place. Measure your slate from the bottom edge to just above the nail hole to determine what reach is required for your particular slate. Some imported slates have high holes and some longer slates (22 inches long and 24 inches long) may be too long for the snow guards you're looking at. If your reach is too high, use Mullane or Salvo retrofit snowguards! Or custom order Gough retrofit snowguards with extra shank length. Call us at 814-786-9085 for custom orders, or send us an email.
Berger snowguards have a 25% restocking fee, so make sure you know your "reach" before buying Berger retrofit snowguards used on larger slates.
If your snowguard reach is inadequate, you will have to remove two slates for each snowguard (one slate above the other), fasten the snow guard between two exposed underlying slates using nails or screws, then re-install the slates over the snowguard. First, slide the lower slate over the snow guard and nail with two nails on the exposed side (one nail above the other), then slide the top slate into place and fasten with a nail and bib, or with a slate hook.