There is plenty of good information on the BrickWood forums about refractory materials — what they are, why they are important, and especially who sells them. HW sourcing centers And all of you moonlighting contractors and advanced weekend warriors who think of the lumberyard as your personal toy box can take that information and turn it into a beautiful wood-fired oven without a lot of thought or discussion.
BUT, if your BrickWood project represents your very first foray into the exotic world of bricks and blocks and the stuff that holds it all together, it may sound like you’re being asked to venture into the realm of Real Men and Real Women who will laugh at your fumbling efforts to describe what you’ve been told to purchase and send you away, humiliated and set back in your determination to have that oven spring to life.
This article is for you.
The process breaks down like this:
Figure out what you need (+)
Read the materials list for your project. Note the quantity called for, which already has a small allowance built in. (An “allowance” is contractor-speak for the fact that there is always some waste in a project, because mixed materials can dry up, bricks may need extra spacing, and so on.)
If you are new to skills like laying bricks, add another 15 percent to the allowance shown in the materials list. You’re learning, so you might mix a bad batch or wildly overestimate how many bricks you can lay before your mortar dries up. Think of it as tuition.
When you’re done, you might find that you need about 460 pounds of High-Temp Pre-Mix mortar for your oven. (400 per the instructions, plus 15 percent, which amounts to another bag.)
Call the Manufacturer or Dealer
As the post linked above shows, most of us live within a decent driving distance of a refractory manufacturer. I’m fortunate to be within 20 miles of a HarbisonWalker center.
DO NOT expect to walk into a nice shiny showroom or even a warehouse. That’s not the way this works. (And if you are able to do such a thing, Yahtzee! you’re fortunate.)
Make a telephone call to the closest distribution center. Tell the salesperson that you are building a pizza oven, that you need 450 pounds of High-Temp Pre-Mix that is weather resistant and suitable for baking use, and that you need recommendations for a product that is suitable. They might ask a couple of questions, but it’s a straightforward request. Then, they will give you a couple of options along with prices. You’ll be able to pay over the phone with plastic, or at pickup with cash.
Get directions to the depot—don’t assume that GPS is enough. My local HW depot is in the back of a strip mall with one small sign out front. If you have a truck, they’ll be glad to place your bags on a pallet and shrink-wrap them, then use a forklift to load it for you. If you don’t have a truck, this is a great time to call in a favor from that friend who keeps asking how they can help. 
Go get your refractory
Go to the depot, check in with the manager (probably the same person who took your order), and verify your materials are ready. You’ll probably need to sign a receipt. Then, you can back your truck up to the dock, wait for your pallet to be loaded, and drive it on home.
Start building
Back at home base, you’ll find it completely impractical to unload your pallet as is. You can break it up while it’s still on the truck—just be careful cutting the shrink wrap. Cutting into a bag would be a bad thing because open bags start absorbing moisture from the atmosphere.
Wheel or carry your bags a couple at a time into your storage area, and you’re good to go.
Among your building memories—the ones that add zest to your delicious pizzas—you’ll recall how you became an expert at sourcing your building materials!