I need to replace a beam under my house.
The existing beam is made from two 2X8s. Over time this slender beam has started leaning in various places along its path. Since it needs to be replaced, I thought I would create a thicker beam of 2X8s. I am thinking of using three or four 2X8s. Not for strength, but for stability.
Here are the three problems I am aware of:
1) The beam needs to be built so that when finished it is perfectly flat on top and bottom. If it is not, it too will start leaning over time.
Will using three or four beams help with this problem since it offers a wider platform? Any ideas for getting it perfectly flat?
2) How does one go about connecting all the 2X8s together? My guess is to nail an "M" pattern of nails that penetrate all layers. And, of course, alter the splices over the piers.
I have used this technique with temporary jacking beams in the past. It works fine, but I am not sure about this approach for a long-term beam.
3) Would you recommend building a single 36 foot beam or building a few short ones?
A single beam appeals to me, but I worry about trying to keep everything flat while building it -- since it would be so long, it would need to be constructed under the house.
Any thoughts appreciated.