01 — The edges
A gap at the side undoes the whole screen
An insect mesh with an open edge is not an insect screen. Mosquitoes do not need a hole — they need a seam. Side retention along the full height of the opening is what makes the difference between a screen that works and one that merely looks closed, and it is the single thing most worth asking about.
- Side retention matters more than mesh specification.
- The bottom bar has to meet the floor consistently.
- An uneven slab changes what is achievable at the sill.