Keep Customers on Your Site Longer -
We typically recommend that you not link to roofing manufacturer websites from your own roofing site because most manufacturers offer a contractor look-up service. The logic is that if you spent the time and money to get a customer to your site, you should keep them there at all costs until they contact you. The internet promotes a short attention span, and keeping visitor's attention is crucial.
Offer the Roofing Information they Need -
The new Roofwebs sites incorporate most manufacturer's information so that customers can find what they are looking for without leaving. Thus you will have a higher retention rate and higher likelihood of getting that customer's contact information.
Using logos that are familiar to customers will help them associate you with known brands, but linking those logos to the manufacturer's website is probably not a good idea.