There are several things to consider when attaching gutters to metal roofing. Most experts agree that using metal strapping is a bad idea. Not only does the weight of the gutter on the strapping cause potential damage to the bottom edge of your metal roof, but you also have the issue of different metal types rubbing together. Instead, a half-round gutter attached to the wood rafter tails with gutter brackets is a good way to go.
Step 1 - Gather Supplies
Before purchasing gutter brackets for your metal roof gutter, count the number of rafter tails under the eaves of your metal roofing and measure the space between them. A rule of thumb is to have about two feet of spacing between gutter brackets. Based on the length of your metal roofing, decide how many gutter brackets you need and choose screws that are the correct size for the holes in the gutter brackets. You want the screws to be quite long with deep threads as they will be bearing the weight of the gutter. Then, cut the half-round gutter material to the appropriate length.
Step 2 - Attach the Gutter Brackets
Use a tape measure and pencil to mark the spot on each rafter tail where you want the gutter brackets to go. If you are attaching the gutter at a slight angle to encourage water to drain toward the downspout, take that into consideration when you mark the position for the gutter brackets. Also, if you are using gutter brackets that screw into the ends of the rafter tails, pre-drill the holes using a slightly smaller drill bit than the size screws you are using. Then, use the drill to securely screw the gutter brackets to the rafter tails you’ve selected to hold your gutter.
Step 3 - Install the Gutter
Now that all of the gutter brackets are in place, you just need to finish installing the lengths of half-round gutter. Start at the end with the downspout, connecting the end piece to the downspout first. Then, slide the length of gutter into the end piece. If you are using plastic gutter materials, you may be able to just set the length of gutter into the brackets and push down firmly to snap them in place. If you are using metal materials, you may need to slide the gutter into the gutter brackets from the opposite end. Either way, the gutter brackets should clip around the top of the half-round gutter length to hold it securely in place.
Attaching a gutter to metal roofing is a simple process so long as you have the wood rafter tails to screw gutter brackets into. Decide whether you want to use metal or plastic gutter materials and determine the appropriate spacing between the gutter brackets. Armed with a drill, long wood screws, and the gutter materials, attaching gutters to your metal roof can happen in 3 easy steps.