The HVAC Portion of getting this wall down was a large part of the project, but there was still a lot more planning that needed to go into it. It became obvious to us pretty quickly when getting quotes for the structural work that choosing a contractor was going to be hard. The quotes were all over the place, with the main difference being the size of the beam. We received quotes for everything from a 11 3/4″ x 5 1/4″ beam to a 18″ x 7″ beam to span our 21′ distance. So how do we know if a beam is big enough to support the weight or if one is overkill? How were the contractors coming up with the beam size? How can we choose a contractor when we don’t have a standard beam size?
To get the beam size, the contractors were going to suppliers and providing measurements and answering questions. The supplier would then tell them the size of the beam necessary. The main things that are important to calculate the load on the beam are the:
- length of the beam
- height and length of the floor joists the beam will support
- number of floors above the beam
- the type of attic (truss or stick framing)
- many other factors
Some of the contractors didn’t actually look at the attic when they visited. Maybe some of their measurements were off. Maybe some of the suppliers may over-size the beam to make a larger sale. All of these things lead to a wildly different beam size.
I called our local lumber yard and provided measurements to them. They told me I would need a 18″ x 5 1/4″ Laminated Veneer Lumber (LVL) beam.
We considered giving that measurement to each contractor and having them re-evaluate the pricing. But this is a big investment and we decided that we should probably bring in a structural engineer to be sure. Structural engineers aren’t cheap (the one we chose charges $150/hr), but in our case we wanted to be sure we had the right size beam for our safety and peace of mind. The engineer came, inspected everything, and took all of his measurements, then went back to the office to run some calculations and make his drawings.
The engineer’s original drawings were for a flitch beam, which is basically two LVLs with steel sandwiched between. When we brought that back to our contractors, some of them couldn’t get quotes because they didn’t know where to get steel like that, and those that could gave us prices all over the place again. Then there was the issue that the beam itself was going to weigh about 800 lbs. and would take a lot of manpower to get it into the house and raise it into place!
We asked the engineer if we could do an all-LVL beam and he gave us a size of 18″ x 7″. There are tables online from LVL manufacturers to calculate beam sizes for your span. Since we are both engineers (albeit not structural), we probably could have done some research on calculating the load and come up with a beam size on our own without paying for an engineer. We probably would have come up with a similar beam size, saved some time, and saved a lot of money. But using the engineer gave us some security in the calculations and prevented having to pay the contractor to make the drawings. Would we recommend using a structural engineer for a project like this? If you have no idea how to calculate the load or use the span tables, then yes. If you have some technical understanding and are willing to work to figure it out, then probably not.
The main reason we would not recommend an engineer in that case is that we got trapped in the cycle of needing the engineer to modify drawings when it came to the beam material and size. We’ll also get into an issue next post that caused us to go back to the engineer for some modifications. Every time we go back to the engineer means $$$$, even for a simple change, and that is frustrating. Have you ever seen the original contract/change order representation? Kind of like that.
After we received the LVL revision to the drawings, we sent them to our contractors and finally we were on level playing ground. There was a lot more than price that went into the decision on contractors of course. One contractor just didn’t give us the impression that he had the experience to get the job done. Another one actually added a fee for “working with a design professional,” which we thought was ridiculous so we nixed him. Another one couldn’t start for 10-12 weeks and was clearly tailored more for clientele that don’t want to get their hands dirty. I told the contractors that I had already done the work of getting the beam sized, had the drawings made, and we were going to do all of the electrical, flooring, trim, and painting; basically we just needed someone to do the structural, framing, and drywall work. We did a lot of the preparation and were very familiar with what needed to be done, we didn’t need a project manager to charge us extra for all the work we’d already done.
We finally found the right guy for the job. He was very easy going and was completely aware of the amount of preparation we had put into this and open to working with us. He has just one small team of guys, which usually means less overhead and lower price. Best of all, he could start very soon. Woohoo! Within a week of signing the contract he could start demo. We’ll talk about that next post!
Do you have experience with beam sizing, structural engineers, or acting as general contractor on your home projects? Let us know in the comments!