I am currently in the process of acting as my own general on a detached garage and an addition to my home. It has been a learning experience and as hard as it's been, I've really had a good time with this. I'll try not to ramble to much.
The permitting process can seem a bit daunting depending on your building inspector. There are those that will do anything to convince a homeowner to hire a general vs. doing it themselves and I've even heard a few inspectors say they will do everything possible to reject a homeowner's bid to be their own general. My first interactions with my building inspector started down this path (asked me if I've ever cut a piece of wood before...haha). I played humble and brought good questions to the table with him and over time, he's warmed up to me. Actually took pictures of the job I did installing/sealing my windows to "show the contractors how it should be done". You really need to build a solid relationship with the bldg inspector or life will be hell. A friend of mine who is pretty arrogant did a similar build and pissed the guy off. He ended up having to bow out as general and hired a licensed contractor to finish it off....$$$$.
Insurance/Workman's comp: Insist on contractors that are licensed and carry insurance. As the general, you have every right to ask for a confirmation their insurance is up to date. You are liable for any injuries to folks that are not covered....it's not easy as some of them show up with different people each day so be vigilant. Oh and get a builders risk policy as well. $200 or so is cheap insurance.
Bids: Get multiple bids for items. I went after on average, 5 bids for each trade I was subbing out. I haven't hired the low bidder yet, nor have I hired the high bidder. I hired the person I felt the most comfortable with and had a reasonable price. I also got bids from 3 General's just to see where I was coming in vs. hiring the whole thing out.
Payments: Make progress payments and be flexible with when you pay. I found that when a sub asks for a "draw" and I pay them on the spot, they tend to work with me better vs. telling them to submit in writing their request and I'll pay in 30 days. Doesn't work that well in residential construction.
Scope: Make damn sure your scope is well defined and it's exactly what you want. Otherwise, you will get the sub's interpretation of what was in the prints and it may not match what you are after. Scrub your prints in depth over and over until you are convinced it's what you want and it's accurate. Even details as small as where the sink is located in your vanity can have an effect on how it gets build. Prints show the sink on the left and you chose a vanity with a sink in the center, could be an issue.
Research the hell out of materials, methods, etc... so you can talk intelligently with the subs about what you want.....otherwise, they may just snow you with BS. (Concrete guy actually tried to talk me out of fiber in my pour....I know it's not rebar but for $3.50 a yard extra, it was added protection during the cure). Be very clear the quality level of materials you expect. If your prints show a door, you're going to get a $20 door when you probably were thinking of a $200 door. Be very wary of scope creep.
What will you own? Here's where I may have bit off more than I can chew but so far I'm keeping up, barely. I decided I just couldn't do my own dirtwork, concrete, plumbing, mechanical, electrical, framing, or stucco. Otherwise I'm doing it all myself. And it's a mad dash to keep up with subs that have 5-10 guys working for them. While I'm saving significant $$ doing a number of things myself, sometimes I wonder if it would have been more prudent hiring out a few things. As the general, you will need to provide a number of things you may not think about: trash management whether it be a roll off dumpster or you hauling the **** to the dump yourself, porta-potty, power, water, etc....unless you spell these things out with your subs before bidding. Be clear about keeping the jobsite clean. I wasn't and to be honest, the majority of subs are absolute pigs. I'm finding fast food bags, soda cans, etc...all over my yard.
Schedule: Here's where I've learned a lot! Understand from your inspector just what the inspections are and what's required. As an example, I had no idea that the framing inspection couldn't be done until the electrical/mechanical/plumbing/fireplace inspections were complete....not a huge thing but nevertheless, it threw me for a bit of a loop at first. For inspections, make sure everything is visible.....inspectors don't put up with pictures of what you did...they want to see it first hand. Don't be the guy that covers up his sheathing with paper/wrap only to find out the inspector wanted to see the nailing patterns on the OSB....you'll just end up spending money to take all the stuff off and putting it on again. Work with your subs to understand how long they need to get their work done and how much notice they need to start. I typically got responses of "call me a week before you need me there" only to find out they weren't available for 2 weeks so be **** about communicating with them (it doesn't hurt that the squeaky wheel gets the grease so to speak). I published a full out project schedule to all my subs with their inputs included and call them weekly (more often actually) with any updates. Unless you are at the site all the time, you will need to rely on the phone, email, and texts to keep everyone in the loop. I manage construction at my job ($100 million in projects last year) and it's always very time sensitive stuff so I endeavored to have no float in the schedule...JIT'd everything. So far, it's worked out pretty well considering this is my first try at this. Understand that if you are buying the doors and hanging them yourself, you'd better have dates figured as to when you should order them so they arrive in time (windows, lumber, fixtures, etc...again, depends on how much stuff you decide you want to own) and you don't hold anyone up. These guys typically jump at whatever work they can find and will string you along as long as they can just to land more work. If you maintain your schedule, it's much easier to keep them engaged and moving forward.
Codes: It's hard to research codes. I just couldn't bring myself to reading the code books to be honest....and when a municipality has about 10 agencies worth of codes attached to their requirements, it's nearly impossible to keep up. Use your subs and inspectors as sounding boards for what is required. Everytime an inspector comes out for an inspection, I'm there to not only develop the punchlist for the subs (I actually do this BEFORE the actual inspection) but also to ask what they are looking for on the next inspection.
Understand that subs work at their own pace mostly. Some will show up for a couple of hours then disappear. Others showed up at 0600 on a Saturday and start framing (not great for neighbor relations!). As long as they are hitting their schedule, I don't care if they visit once to do the work or 10 times to do the work as long as it gets done.
Neighbor relations: Spend a bit of time walking the neighborhood and letting folks know what you are up to. Take a set of prints (preferably the ones approved by the building inspector in case you have any grumpy neighbors), a rough schedule, etc... and have a quick conversation with your neighbors. Give them a number you can be reached at should their be any issues etc... Neighbors can cause serious issues if they are not happy with what's going on so like the inspectors, you should keep them happy.
While it's still early to tell for me, all indications are that I will save significant $$ contracting it myself. The 3 generals that bid it came in around $175/SF for the addition and $35/SF for the garage (it's pretty bare bones). For the addition, I planned to come in at around $95/SF and so far I'm pretty well on track for that. The garage was pretty close to a wash as I'll come in around $32/SF. All in all, I stand to save around $65k doing this myself which will just add that much more to my equity in the place. Of course, I'm running mad trying to keep up (lost 20 lbs over 8 weeks at this point...which isn't a bad thing! and just had knee surgery due to pre-patellar bursitis which was completely unexpected) but I'm starting to see the point in the project when it's just me getting things done and then the subs come back for their final. The pressure will still be high but not nearly as high as trying to coordinate the framing, roofing, waterproofing, etc.... in the middle of monsoon season here!
Sorry as I think I rambled! Bottom line is to do your homework, make sure everything you want is clearly spelled out, have a good schedule and communicate more than you think you need to. Subs don't like surprises so keep the gotchas to a minimum.
Regarding your price from your general of cost plus 10%, that's not bad at all. In fact I find it very low so that may be your best bet. Oh, one last item then I'll go. Get lien releases from all your subs suppliers or ask for receipts for their materials (or you buy them yourself). Otherwise, if they don't pay their bills, the supplier can come after you for payment.
Ok, fingers are tired and I need to go order some insulation and install some windows!
Cheers,
cc