Hi Mick, and thank you for using Just Answer.
The size of "I" beam you can use easy enough would be 398.0 mm. This measures end to end. The inside of the "I" should measure 360.40 mm. The measurement of the "I" across should measure out to be 141.8 mm. This chunk of steel will take the load of the building plus what you intend to use it for. This will also allow extra weight load if you happen to live in an area that produces winter snow that piles high, and is heavy. You may also want to consult the building planner to confirm what I recommend. He should say it's a bit heavy, however it will give you the added strength you need for the days you push the 150k weight you want to pick up. I wish you the best.
thanks for your reply.
Massive snow is never a problem where I live in England. And will be easily removed if there is a build up so a lighter steel may be appropriate. thanks again for your input. MICK
You're welcome. Just a thought here but there will be a point in life that you may want to sell your home. If you set this "man shed" up right, it would be a great selling point to your property. Just remember that the lady looks at the house, and the man is always interested in what's outside for him to "play" in. Having a heavier "I" beam in place may make a difference. I understand about the cost right now, but you will pick that up on the back side plus more. I wish you the best. If you like my service please rate. Anything else I can do, just let me know.
Many thanks yet again for your advice. I can see where you are coming from with a view to future property sale. This is something I considered prior to initial thoughts of the build.