Correct my grammar please

[Alexander]

Hi, I my grammar in the letter below correct? Thanks.

This is to inform you of the accumulation of grease in the drainage pathway in the corridor going to your company at the ground floor, which according to our maintenance personnel, comes from the downspout PVC pipe of your canteen at the roof deck.
Said drainage pathway together with the improvised urinal at the back of your Security Guard's barracks contributes to a foul smell that causes people passing by that corridor to complain.
We request that appropriate action be taken by your office on this matter.
Thank you very much.

[emsr2d2]

Hi. Is my grammar in the letter below correct? Thanks.

This is to inform you of the an accumulation of grease in the drainage pathway in the corridor going leading to your company premises at on the ground floor, which, according to our maintenance personnel, comes from the downspout PVC pipe of your canteen at on the roof deck.

Said drainage pathway, together with the improvised urinal at the back of your Security Guard's barracks, contributes to a foul smell that causes people passing by that corridor to complain.

We request that appropriate action be taken by your office on to remedy this matter.

Thank you very much.

See my changes above. Is there only one security guard?