Help - why do need construction materials?

[Neoo]

Help - why do  need construction materials?
( i from russia)(cannot write)

[Corwin]

I believe that we gave an expert in that field - Dave, please explain.

[Different]

I believe that we gave an expert in that field - Dave, please explain.

  ...  : .... hahhaha 

[Neoo]

why should they?

[Different]

I believe that we gave have an expert in that field - Dave, please explain.

[Mylet]

Construction materials can be thrown at construction sites to construct things like siege towers, catapults or healing tents.
Depending on what you construct, you need more or less construction material.

[krampe]

The most important fact is that they are noob magnets in sieges.
Drop them at frequently visited spot and you catch 5+ people hacking on one even when they could jump over or walk around it.
But beware that you don't stack up a too big group that you get overrun after it is destroyed.

P.S. I mixed material and sites here, i was refering to sites though.