The payment terms for such work will generally vary as you have noticed. Usually up to 1/3 upfront is somewhat standard, but there are no hard and fast rules. You may see all material cost as being paid upfront with a couple labor payments, or on something like your project which is fairly large the work broken down into phases with the phase materials being paid prior to starting the phase and phase labor being due upon completion of the phase. Contractors will have their own terms that work well for their business and the way they work. If all the payment terms proposed work for you the choice should be based on the reputation/quality of the contractor. If you have a preference of one contractor and their payment terms don t fit with your budget you might try working something out. Good luck.
For a big job like this, it s not unusual to have to pay about 30% up front. But you should NOT do that until you ve checked out the contractor with the better business bureau and your state s contractor s board (if there is one), and checked some references, AND have a real contract to sign.
For this kind of a job I would ask for more than 3 quotes. And you might want to consider an escrow service, I would be very cautios with making a big down payment.By the way, if you want free bids, I use the renov. experts - they have local contractors that they pre-screen so you only get estimates from those who made the cut.You can contact them to get free estimates for your job. If you want, here is the link I used - http://best-offers-online.com/estimates
No more than 2/3 the cost of the materials.
We have built several houses and have done extensive remodeling, first and foremost check out the contractor and his references. Go look at his work. Find out if he is licensed and insured. Better to pay a bit more for good work than to have someone scam you and run off with your money. I would pay no more than 25% of the material cost. If he is a reputable contractor he has accounts where he buys his materials, therefore his bills are not usually due until 30 days after the purchase. Then pay him progress billings based on the amount and quality of the work done. If something is not right do not pay him until it is made right. Have your expectations in writing. If it ends up in court, he will win, unless you have a detailed document that proves what he was suppose to do and for how much. If you are not satisfied, take pictures. This is extra work up front on your end, but it is far better than having shoddy work or someone who just leaves with your money. Any professional will work with you - doing an entire home remodel for $19,000 seems fairly low. You mention plumbing and wiring as needed, before you proceed make sure they fully explain costs for any as needed project. Wiring and plumbing can get expensive, take your time, do it in writing and try to be available daily to answer his questions and check his work.