As seen on this  website the damage the bees do to a wood structure can be significant. There are bee traps that are available but very unsightly and there are some expensive bee killer solutions that you can purchase or the other option is hiring an exterminator. The solution to this problem can be made fairly simple with these following ingredients and you`ll have one of the best bee killers that exists. The cost is $7.99 for the directions through Paypal, also available is the complete kit for $34.99 the kit contains the directions and supplies to make several syringes of the bee eliminator(one syringe will treat approximately 200 holes),which will save you the hassle of finding the supplies on your own. It`ll be money well spent .Go to"  http://www.ebay.com/itm/Carpenter-Bee-Trap-Killer-Complete-Do-It-Yourself-Kit-/141661089170?pt=LH_DefaultDomain_0&hash=item20fba8ad92 "  to purchase. Also email me if you want the directions only for $7.99.I`ll email those to you after payment.Any questions email me at pxtein@nalu.net.