Foam filters employ the principle of displacement there is nowhere for the debris to go because the gutter is mostly filled with this material.
Do foam gutter inserts work.
Do any gutter guards really work.
However a foam gutter guard collects water just like a sponge and often times becomes trapped within the guard.
Not only does gutter guard foam only last for a few years it is also ineffective.
As a result debris gets trapped at the surface of the foam.
The material itself is highly porous.
Foam inserts or filters are the simplest forms of gutter protection.
Most sponge gutter guards consist of an open cell polyurethane insert or an insert made of foam.
Sponge gutter guards are a do it yourself product and can be found at most home improvement stores.
It is designed to allow the pores within the sponge like material to let water pass through to your gutters and down your downspouts.
In fact gutter guards are extremely useful in many ways.