Reading Two Deck Quotes Side by Side

Two quotes land for the same back yard. One says $26,400 and one says $32,900. Both are for a 320 square foot composite deck with a rail and a stair. The obvious conclusion is that one builder is expensive.

The likelier conclusion is that they are not quoting the same deck. Seven lines usually explain the gap, and none of them are visible in a total.

1. Joist spacing

Composite decking normally requires joists at 16 inches on center for a perpendicular board layout and 12 inches for a 45 degree diagonal, with stair treads tighter again. The manufacturer instruction governs and it is what the inspector checks.

Going from 16 to 12 inches on center uses a third more framing lumber and a third more labor setting it. On a 320 square foot deck that is a real number. A quote that does not state joist spacing has left the biggest hidden variable unstated.

2. Footing depth and count

Footings bear on undisturbed soil at least 12 inches down or below the frost line, whichever is deeper, and the frost line governs in the Treasure Valley. The City of Boise publishes 24 inches as its minimum footing depth for the valley.

Depth costs money, and so does count, because footing count comes from the beam span and the load path. Two quotes with different beam layouts can have meaningfully different footing counts for identical decks.

3. How it attaches to the house

An attached deck bolts to a ledger, which means opening the siding, fastening into structure, and installing corrosion resistant flashing over the top. A non-ledger deck stands free on its own posts and beams, which needs more footings and more framing but avoids the wall entirely.

They are different jobs with different costs, and both are legitimate depending on the house. A quote should say which one it is. Where the wall construction is old or unknown, free-standing is often the better engineering answer even though it prices higher.

4. Whether the stairs are in there

Stairs are a separate scope and they are frequently excluded or minimised. A three-riser step to the lawn is a few hundred dollars. A flight from a deck four feet up, with 2x12 stringers, three of them minimum on a cut-stringer run, a footing under the bearing point, a handrail returned at both ends, and a landing at the bottom, runs $3,200 to $7,500.

If one quote has a stair line and the other does not, that alone can be most of the gap.

5. Which rail system it is

Rail is priced on the open perimeter, and the spread between systems is enormous: $45 to $80 per linear foot for wood, $75 to $130 for composite, $80 to $140 for aluminum picket, $110 to $190 for cable, $180 to $300 for glass panel.

On about 50 feet of open edge that is a range from $2,250 to $15,000. Two quotes specifying different rail systems are not comparable at all until both are priced on the same one.

6. Permit, and who is doing it

A deck attached to the house, over 200 square feet, or more than one story requires a permit from the City of Meridian Building Services Division. Somebody files it, and somebody meets the inspector at the footing stage and again at final.

Ask that permit fees appear as their own line rather than being absorbed into a total. That way you can see what was paid, and you can see whether both quotes included it.

7. Demolition and the wall behind it

Where there is an existing deck, removing it runs $900 to $3,000 including disposal. The part that gets left out is repairing the wall where the old ledger came off. Siding has to go back, and flashing has to be done properly, and if that is not in the quote it is either coming as a change order or it is not happening.

What a comparable quote looks like

Five lines and a schedule:

• Footings: count, diameter, depth.
• Framing: joist size and spacing in inches on center, beam size, attachment method.
• Decking: specific product, color, fastener type.
• Rail: system, and price per linear foot.
• Stairs: riser count, width, what the stringers land on.
• Permit and inspection: who files, who meets the inspector, fees shown separately.
• Start date and build window, in writing.

None of that is unusual to ask for, and a builder who works Meridian regularly will have all of it available. Two detailed quotes tell you more than three vague ones, which is worth remembering before collecting a fourth.

The cost guide works through what each line should run in this valley, the glossary defines the terms, and the cost estimator gives you an independent range to hold both numbers against.