When it comes time to buy a ladder, most contractors show up at their suppliers ready to buy, not to shop features. But you should definitely shop around before you buy to make sure you're getting the best tool for your needs. Here are some things to keep in mind the next time you're roaming racks for a ladder.

Best Sellers

Professionals almost exclusively use Type 1A ladders rated for 300 pounds of load. They're heavier and more heavy-duty than the lighter, more flexible Type 1 (rated for 250 pounds) ladders. Industry-wide, 24-foot extension ladders and 6-foot stepladders lead the way in sales.

For getting on the roof of a typical two-story house, however, a 28-foot extension ladder–not the better selling 24-footer–is ideal. The 28-footer's rails extend the requisite three feet past the eaves. They allow for three feet of overlap between the ladder sections at full extension, which provides the best rigidity and stability. A 24-footer will probably reach the gutters, but as you'll discover when you're hanging by the shingle tabs, trying to find the top rung with your toes, it's just not quite enough. As far as stepladders go, anyone who's pulled wire through ceiling joists, installed a suspendedd ceiling, or hung crown can attest that a 6-foot stepladder pretty much covers all the bases on a "inside" job.

Materials

Fiberglass is the best-selling ladder material. It won't conduct electricity –a major plus –but is noticeably spongier than aluminum. Fiberglass is also heavier, which is important to consider at the longer 32- and 40-foot lengths.

If you want the best combination of strength and weight, aluminum is the material of choice. That's why you'll find lots of aluminum in the hands of painters and roofers who are always climbing and repositioning their ladders.

Most of the aluminum stepladders out there are Type 1, not Type 1A, and are rated for 250 pounds of load. Again, you'll find these used frequently by painters who don't have to climb very far but are constantly on the move.

I last saw a wooden extension ladder on a jobsite in 1984. It had so much spring it felt more like a trampoline than a ladder. The last wooden stepladder I climbed was missing so many bolts and wobbled so much I needed sea legs to stand on it.

Although fiberglass and aluminum have almost completely taken over the stepladder market, you can still find Type 1 and 1A wooden extension ladders for sale. They're certainly stiffer than the old ladder I had. They're popular in the Northeast, especially in cities where theft is a problem. Because of their lower cost, a lot of builders consider them expendable.

Safety

Any ladder manufacturer will tell you there's no excuse for not knowing how to properly set up and use its products. From a 2-foot stepladder to a 40-foot extension model, everything you need to know about a ladder is printed on labels stuck to the rails. "Ladder literature" covers everything from set up to safety to adding accessories. Climbing to the soffit of a three-story townhouse is dangerous enough even if you know what you're doing. If all of your ladder's stickers are covered with paint or have chipped off, you can review safety procedures online at manufacturers' Web sites. Or call them directly to get the latest safety information. (See Sources of Supply on the next page).

Chances are if you're buying a ladder you'll also want some accessories. Levelers, stand-offs, rail caps, and ladder jacks all should be selected carefully for appropriate use with your ladders and applications. A new OSHA regulation governs ladder jacks: "Ladder jacks can only be used on Type 1 or 1A industrial ladders and are not to exceed a height of 20 feet. Plank width must be a minimum of 12 inches wide and the maximum span is 8 feet long (if you're using a wood plank). Fall protection is also required at heights above 10 feet."