Installation steps for Tile Valleys
Use the coloured arrows in this image together with the instructions below.
Arrow key:
- Orange line – approximate outside edge of the mesh
- Green arrows – tile ribs being cut around
- Blue arrows – half-tile adjustments to bring the mesh back into alignment
- Purple arrow – tile to slide upward for access
- Black arrow – optional relief cut for inserting a chisel
- Red arrows – section tucked under the tile (20–30 mm back)
- Yellow arrows – front tab, trimmed later
- Pink arrows – cut along the tile rib and silicone bead
Main objective
Keep the outside edge of the mesh following a reasonably straight line up the roof while lining the cuts up with the ribs of the tiles. The orange line shows the approximate outside mesh edge and the green arrows show the tile ribs being cut around.
Ideally, the mesh should move one tile across for every one tile row up the roof. However, roof valleys are rarely perfectly straight in relation to the tile pattern. As you move up the valley, the tile ribs may gradually move closer to or further away from the valley.
For this reason, on longer valleys you may occasionally need to move across half a tile to bring the mesh back into alignment. The blue arrows in the photo show examples of this. Some sections may therefore span approximately 1.5 tiles, while other sections may only span half a tile.
1. Align the mesh before you start cutting
Start at the bottom of the valley and position the mesh as close to the centre of the valley as practical.
Move the mesh sideways until the outside edge either lines up with, or covers, a suitable tile rib. This is approximately the line shown in orange.
Now check the position at the top of the valley as well.
Before making any cuts, spend a little time finding the best overall position. The aim is to achieve as many sections as possible where the mesh moves one tile across and one tile up, while keeping the number of half-tile adjustments to a minimum.
Once you are happy with the line, keep checking the top of the mesh as you work. If the mesh starts to creep slightly out of position, gently realign it so it continues to finish in the intended position at the top of the valley.
2. Start at the bottom of the valley
Begin cutting and fitting from the bottom left-hand side of the valley and work upwards.
Starting at the bottom is important because the finished mesh will follow the waves and contours of the tiles. As it settles into the tile profile, the mesh can shorten slightly. Working from the bottom upwards allows this small amount of contraction to occur without pulling on mesh that has already been fitted.
The tiles generally lift from right to left, so beginning on the left-hand side also makes it easier to gain access underneath the tile you are working on.
3. Lifting the tiles on the left side
The preferred method is to slide the tile immediately to the left of the tile you are working on upward. This is the tile shown by the purple arrow.
Doing this gives you much better access to the tile you are working on and makes it easier to tuck the mesh underneath.
If the tiles are too firmly locked together to slide upward, carefully insert a wide chisel or large flat screwdriver well underneath the tile rather than just under the edge. Spreading the load further underneath the tile reduces the chance of chipping or breaking the tile edge.
If access is still difficult, there are a few other options:
- You can cut a small relief section in the mesh at the position shown by the black arrow. This allows the chisel or large flat screwdriver to be inserted underneath the tile at approximately a 45-degree angle. The cut-out also gives you enough room to tuck the mesh underneath the tile while the chisel is still holding the tile up.
- Another option is to make the tab between the two yellow arrows wider by extending it across to the next rib on the left. This means the innermost tile does not need to be lifted in order to tuck the mesh underneath the next tile. With this method, the wider tab must later be trimmed back with approximately 1–2 mm of interference against the front of the tile. The slight interference is important because it helps hold the mesh down; cutting it flush is generally not enough with this method.
- If neither of these methods is practical, the chisel can also be worked underneath the mesh from the right-hand side and then underneath the tile. This method can be used where necessary, although it is generally the least preferred option.
Take care not to force or crack the tiles.
4. Make the first cut on the left side
Before lifting the tile, cut the mesh approximately 20–30 mm back from the front edge of the tile. This is the section shown between the red arrows.
Do not cut this section flush with the tile. The extra 20–30 mm of mesh will later be tucked underneath the tile.
Next:
- Cut forward towards the front of the tile at the first yellow arrow.
- Cut a small curved section approximately 20 mm back around the tile profile, following the area indicated by the blue curved line.
- Continue the cut back out to the second yellow arrow.
You should now have a small tab of mesh following the shape of the front of the tile.
Tuck the section between the red arrows underneath the tile.
Leave the mesh between the two yellow arrows sticking up for the moment. This section will be trimmed later.
5. Cut along the tile rib
Next, cut down the tile rib to the second yellow arrow, following the line shown by the pink arrow.
Make the cut around 10 mm on the valley side of the rib, rather than directly over the top.
This allows the finished edge of the mesh to sit neatly against the side of the rib and also helps hide the silicone bead when the valley is viewed from ground level.
Continue this process one row at a time as you work up the valley.
Keep checking the position at the top of the valley as you go. If the mesh moves slightly while being shaped around the tiles, gently move it back into alignment so it still finishes where you originally planned.
6. Fitting the right-hand side
The right-hand side is generally easier because the mesh is already mostly shaped and held in position.
On this side, make the vertical rib cut first, approximately 10 mm on the valley side of the rib.
Then make the cuts across the front of the tile to form the section that will tuck underneath.
Because the mesh has already been shaped and secured on the opposite side, there is much less movement at this stage. The section between the two yellow arrows can therefore be cut to its finished length straight away.
For the best fit, cut this section flush with the front of the tile, or leave approximately 1–2 mm of interference so the mesh presses gently against the front of the tile. This can help stop the mesh from lifting.
Carefully insert a wide chisel or large flat screwdriver well underneath the right-hand tile and gently lift it. This will also lift the overlapping tiles to the left enough to allow the 20–30 mm mesh tab to be tucked underneath.
If the mesh is already sitting neatly and holding its position, you do not have to complete each row one at a time. You can make the cuts for several rows at once, then lift the tiles and tuck the mesh underneath afterward.
7. Finishing the top of the valley
At the top of the valley, trim the mesh to follow the shape of the roof and pointing.
Bring the edge of the mesh into contact with the pointing.
Push the edge of the mesh down firmly so it slightly bites into the pointing and sits securely against it.
Try to keep the finished shape neat and symmetrical across the top of the valley.
8. Trim the remaining front tabs
Once the mesh has been completely fitted, work back down the valley.
Trim any remaining tabs between the two yellow arrows.
The ideal finish is flush with the front face of the tile, although leaving approximately 1–2 mm of interference can work even better. The slight pressure against the tile helps stop the mesh edge from trying to lift away.
9. Seal the cut edges
Use a colour-matched roofing silicone to finish the installation.
Apply a thin bead of silicone along the exposed mesh edges where the mesh has been cut beside the tile ribs, including the areas indicated by the pink arrows.
Seal any small gaps created around the front tile cut-outs.
At the top of the valley, apply a slightly larger bead of silicone along the pointing where the mesh finishes.
Important – keep mesh offcuts off the roof
Small pieces of cut aluminium mesh can be very slippery if stepped on, particularly on a tiled roof.
As you make each cut, place the offcut straight into a container such as a Tuff Tub, bucket or similar container, rather than leaving pieces lying on the roof.