How Eavestrough Screws Work Loose

Did you ever wonder what keeps your eavestroughs from falling down? Well the truth is they attach to the ends of rafters protruding from the roof space. However, these are grain-on wood which is not always the best surface to attach things too. We wrote this article to explain how the screws may come loose.

Various Ways to Screw Eavestroughs Down

1… The easiest method involves driving a screw through the upper lip of the inner wall directly into the timber. However, the outer wall may distort from debris blocking flow over time.

2… As an alternative, a longer screw may pass through both the outer and inner walls. In this case there’s a spacer to avoid pulling the upper wall inwards.

3… Sometimes, supporting brackets are used as an additional refinement. This increases the support, but may spoil the clean lines of the eavestrough from below.

Why the Type of Screw Really Matters

Decent wood screws with tapering spiral threads follow pre-drilled, undersized holes as they literally squeeze themselves into position. They perform best when they screw across a grain compared to into it.

Screw plugs also work under these circumstances, especially when hammering a matching screw but tightening it the last couple of turns. Serrated nails are less effective, because they may pull out if the surrounding wood softens.

However, we can’t recommend constant diameter, self-tapper metal screws that force their way through. That’s because they don’t have sharper, coarser threads, and a tip enabling them to cut cleanly into wood without the risk of spitting the grain.

Using the wrong screws on eavestroughs to force-fit an attachment is therefore a false economy. This is the number one cause of loosening in a storm and eventually failing completely.

However, the Condition of the Wood Matters Too

A screw of any kind is only as strong as the wood it attaches to. If the rafter ends are permanently moist, rotten or split then the bond is weak and will eventually fail. Unfortunately, many cowboy operators get away with this, perched on ladders out of reach of clients.