Can a landlord hold a security depositdue to pre-existing conditions?

Who is responsible for the leaky roof depends on a a few things.  Generally speaking, a roof would be a major repair and the responsibility of the landlord. If the leaking was caused by the tenant - whose kids snowboarded down the roof? - then the burden could shift toe the tenant.  Here is the law with regard to security deposits.  Take a look and act accordingly.  Good luck.

"In Colorado the landlord is required to send a written statement of damages, along with any security deposit refund, to the renter's last known address. When you leave an apartment, the landlord has one month (unless a longer period of time, not to exceed 60 days, is stipulated in the lease) to send to your last known address the full amount of the security deposit or a written list of the damages and the amount of money needed for repairs. If the deposit is larger than the amount required for repairs, the landlord must return the excess.  If the landlord does not comply with the law and fails to refund the deposit within one month (or up to 60 days if stipulated in the lease), or withholds any portion for normal wear and tear, or if you consider the reasons for withholding invalid and wish to pursue the matter, you can take legal steps. You may seek the assistance of an attorney, file a complaint in county court under Simplified Civil Action, or file a complaint in the small claims division of county court. o start the action, send the landlord a certified letter (with a return receipt requested) and demand the deposit be refunded within seven days under threat of legal action. Also send a copy by regular first class mail. The letter should cite violation 38-12-103 of Colorado Revised Statutes and mention that the statutory time requirement for returning the deposit has elapsed following the termination of the lease agreement. If the landlord does not respond within seven days after the letter is sent, you can pursue court action."