How do I estimate materials for a deck?

Start with three numbers: deck size, joist spacing, and local frost depth. Then estimate section by section from the ground up: footings and posts, beams and ledger, joists and hangers, decking (square footage divided by board coverage, plus 10 percent waste), fasteners, and railing. Write it all as one list, specific enough to price each line.

What materials do I need to build a deck?

A deck needs footings (concrete and tube forms) and post anchors, posts and beams, a ledger board with structural fasteners, joists with one hanger per end, a rim joist, decking boards, deck screws or a hidden-fastener system, and railing (posts, rails, balusters and hardware). Add a 5 to 10 percent waste factor on cut lumber and decking.

How do I not forget any deck materials?

The items most often forgotten are joist hangers, footing concrete, railing hardware, and enough fasteners. With Buildsavr you drop in your list and an AI agent flags common misses for a build like yours before you buy, so the list is complete. Then it prices everything at once.

How do I get the cheapest price on deck materials?

No single store is cheapest on framing, decking, and fasteners at the same time. Buildsavr prices your whole deck list across every major retailer near you and returns a store-by-store buying plan showing the cheapest place for each item and your total. It is live in Quebec and expanding across Canada and the US.

Can I just take a photo of my deck list?

Yes. Snap a photo of your handwritten or printed list, or drop an Excel or PDF, and the AI plan reader parses it into line items, matches each to the right product, and prices it in about 30 seconds. You can also chat the list and let the AI agent help build it out.

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How to estimate materials for a deck (and buy it for less)

By Simon Lafortune, Co-founder, Buildsavr · July 3, 2026

A deck is one of the most satisfying builds you can take on, and one of the easiest to overspend on. Not because decks are expensive, but because most people estimate the materials loosely, buy everything at the first store, and pay list price on every board.

You can do better with two moves: a real material estimate, and a real price comparison. This walks through both, so you know exactly what your deck needs and exactly where to buy each piece for the least money.

Every board: framing, decking, fasteners, footings
AI agent: catches the items you forgot
Store by store: the cheapest plan to buy the whole deck

Start with the deck plan and the numbers you need

Before you count anything, you need three numbers: the deck size (length by width), the joist spacing you are building to (usually 16 inches on center, or 12 for some composite decking), and your local frost depth, which sets how deep the footings go. With those, every material quantity falls out of the plan.

If you do not have a drawing, sketch one. Even a rough top-down with dimensions and post locations turns a vague idea into something you can estimate and price.

Estimate the materials, section by section

Work the deck the way you build it, from the ground up. Estimate each section, add a waste factor on anything you cut, and write it all as one list.

Footings and posts: one footing per post (posts usually 6 to 8 feet apart), concrete tube forms and bagged concrete per hole, plus post anchors.
Beams and ledger: beam stock sized to your span, a ledger board against the house, and the structural fasteners or lag screws to attach it.
Joists and hangers: joists at your spacing across the span, a rim joist around the frame, and one joist hanger per joist end.
Decking: total square footage divided by the coverage of one board, plus 10 percent for cuts, waste, and the pattern.
Fasteners: deck screws or a hidden-fastener system, sized to your decking and joist count. Buy by the box, not the handful.
Railing: posts, top and bottom rails, balusters or panels per linear foot of railing, and rail hardware.

The two mistakes that blow a deck budget

The first is an incomplete list. You estimate the framing and the decking, forget the hangers, the concrete, the railing hardware, and half the fasteners, then pay full trip cost to grab them mid-build. The small stuff is where deck lists leak.

The second is buying it all at one store. Pressure-treated framing, deck boards, and fasteners are almost never cheapest at the same retailer in the same week. Buy the whole deck in one place and you are paying that store's markup on the lines it happens to run high.

Let the AI plan reader complete and price your list

This is where Buildsavr does the heavy lifting. You drop your deck list in however you have it, typed, a photo of your notes, an Excel sheet, a PDF, or just by chatting it out, and the AI plan reader turns it into matched line items.

An AI agent then helps close the gaps. It flags common misses for a build like yours, the hangers you forgot, the concrete for the footings, the railing hardware, so the list is complete before you spend a dollar. You confirm the quantities, and it prices the whole thing.

What you get back is a buying plan for the entire deck: which store is cheapest on the pressure-treated framing, which wins on the deck boards, which has the best number on fasteners, your total, and how much you save versus buying it all in one place. In Quebec today that compares Home Depot, Rona, Canac, BMR, Patrick Morin, Home Hardware, and more, in about 30 seconds.

A realistic picture

Take a simple ground-level deck: pressure-treated framing, composite or PT deck boards, joist hangers, structural and deck screws, concrete tube forms, and railing. Buy all of it at the first store you drive to and you pay that store's price on every line, including the ones it marks up.

Price the same list across every retailer and it almost always splits: one store clearly wins the framing, another the fasteners and hardware, and the deck boards land in between. Following the cheaper option on each line, only where the difference is worth the stop, is how a deck you already designed gets meaningfully cheaper without changing a single thing about it.

Frequently asked questions

How do I estimate materials for a deck?: Start with three numbers: deck size, joist spacing, and local frost depth. Then estimate section by section from the ground up: footings and posts, beams and ledger, joists and hangers, decking (square footage divided by board coverage, plus 10 percent waste), fasteners, and railing. Write it all as one list, specific enough to price each line.
What materials do I need to build a deck?: A deck needs footings (concrete and tube forms) and post anchors, posts and beams, a ledger board with structural fasteners, joists with one hanger per end, a rim joist, decking boards, deck screws or a hidden-fastener system, and railing (posts, rails, balusters and hardware). Add a 5 to 10 percent waste factor on cut lumber and decking.
How do I not forget any deck materials?: The items most often forgotten are joist hangers, footing concrete, railing hardware, and enough fasteners. With Buildsavr you drop in your list and an AI agent flags common misses for a build like yours before you buy, so the list is complete. Then it prices everything at once.
How do I get the cheapest price on deck materials?: No single store is cheapest on framing, decking, and fasteners at the same time. Buildsavr prices your whole deck list across every major retailer near you and returns a store-by-store buying plan showing the cheapest place for each item and your total. It is live in Quebec and expanding across Canada and the US.
Can I just take a photo of my deck list?: Yes. Snap a photo of your handwritten or printed list, or drop an Excel or PDF, and the AI plan reader parses it into line items, matches each to the right product, and prices it in about 30 seconds. You can also chat the list and let the AI agent help build it out.

Estimate your deck, then buy it for the lowest total

Buildsavr is live in Quebec and rolling out across Canada and the US. Join the waitlist and we will tell you the day it launches in your area. Free to compare, no credit card.