Composite Deck Cost in Northern Virginia
Compare budget scenarios for your deck, understand what a price includes, and prepare a written installation estimate with Loudoun Decks.
Planning a composite deck in Northern Virginia? Start with a measured scope and a written estimate.
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How much should you budget for a composite deck?
For a 400-square-foot composite deck, this calculator models $28,125 - $51,300 with Trex Transcend, one stair flight and composite railings. This is an illustrative budget, not a Northern Virginia market average or a quote. Actual installed cost depends on the measured design, framing, site access, permits and written inclusions.
By Loudoun Decks Team. Updated September 13, 2026: calculator assumptions, quote inclusions and manufacturer references.
Composite deck budget calculator
Choose a size, material and optional features. The result is a scenario built from preset rates and a planning adjustment. It does not measure your property or establish a supplier price. Railings and stairs are optional inputs; verify all required work before treating any total as a project budget.
Configure Your Deck
Illustrative Budget
Base Deck (400 sqft × Trex Transcend)
$18,000 – $26,000
Add-Ons
+ $4,500 – $12,000
Scenario total with a 25-35% planning adjustment
$28,125 – $51,300
Selected options only. Confirm demolition, framing, permit fees and cleanup in your written estimate.
About this estimate
These preset assumptions illustrate how size and options affect a budget; they are not supplier quotes, completed-project prices, or a measured Northern Virginia average. The 25-35% adjustment applies to the base and selected add-ons. It is a model assumption, not a verified local premium. A property-specific written estimate determines actual scope and price.
Composite deck cost by size: calculator scenarios
Every row uses the calculator's Trex Transcend assumptions: $45-$65 per square foot, then a 25%-35% adjustment. The second scenario also adds $1,500-$4,000 for one stair flight and $3,000-$8,000 for composite railings before that adjustment. These are arithmetic examples, not surveyed prices or completed Loudoun Decks projects.
| Floor area | Base scenario | With one stair flight and composite railings |
|---|---|---|
| 200 sq ft | $11,250 - $17,550 | $16,875 - $33,750 |
| 300 sq ft | $16,875 - $26,325 | $22,500 - $42,525 |
| 400 sq ft | $22,500 - $35,100 | $28,125 - $51,300 |
| 500 sq ft | $28,125 - $43,875 | $33,750 - $60,075 |
Actual railing length, stair height, structural work, demolition, permit fees, electrical work and access are not measured by this table. Ask for them to be included or excluded explicitly in your proposal.
What should a written composite deck quote include?
Compare quotes against the same scope: footprint, structure, board collection, railing length, stairs, demolition and approvals. Ask each contractor to identify quantities, allowances and exclusions. A lower total may reflect less work. Resolve missing items and the treatment of hidden damage before comparing payment terms or choosing a contractor.
| Scope item | Get this in writing |
|---|---|
| Decking | Brand, collection, color, board profile, layout, border and fastener system. |
| Existing deck | Demolition and disposal; which structural members are retained or replaced. |
| Structure | Footings, posts, beams, joists, ledger and flashing work; inspection or design dependencies. |
| Stairs and railings | Number of flights and landings, stair width, railing length and specified system. |
| Finishes and electrical | Fascia, skirting, lighting, outlets and any separately priced electrical work. |
| Approvals | Responsibility for drawings, HOA submission, county permits, fees and inspections. |
| Contract terms | Allowances, exclusions, quote expiry, payment schedule, change orders and written warranty terms. |
Choose the relevant scope: full replacement, resurfacing, structural repair, or a covered deck. A screened porch adds a different enclosure and roof scope.
Trex vs TimberTech vs AZEK: compare the exact collection
TimberTech includes both composite and Advanced PVC decking, also known as AZEK. Compare the actual collection and board profile with your Trex or Fiberon option. There is no universal brand price premium: the railing, structure, fasteners, availability and finish scope affect the installed total.
Use the material comparison guide for product-specific sources, samples and warranty questions. A warranty duration does not establish how long your entire deck will last.
A manufacturer's material calculator also has different inclusions from an installation quote. Trex's material calculator states that labor is calculated separately.
How should you handle material price changes?
Ask for the proposal's expiration date, named product availability, substitution policy and treatment of later price changes. A tariff headline alone does not establish the price of your selected decking or railing. Current supplier pricing and the signed contract determine which costs are included and who carries changes after approval.
What drives the price of a composite deck?
Deck size is only the starting point. Compare framing and footings, height above grade, stairs and landings, railing length, board collection, trim, demolition, access and electrical work. Two decks with the same floor area can require very different work. Ask each contractor to price the same design and list exclusions.
Is composite decking more expensive than wood?
Composite can have a higher upfront material cost than pressure-treated wood. Its maintenance requirements differ: capped composite generally avoids routine staining and sealing, but still needs cleaning. Compare the installed scope and the care instructions for the exact board. Maintenance savings depend on your exposure, cleaning choices and ownership period.
Which composite brand is best for budget planning?
Compare specific board collections rather than brand names alone. Trex offers multiple composite collections; TimberTech offers composite and Advanced PVC decking, also known as AZEK. Ask for the same framing, stairs, railings and finish details in each option so the price difference shows the material choice rather than a change in scope.
Do permits affect composite deck cost?
Permit-related costs depend on the jurisdiction and work proposed. Drawings, structural design, permit fees and inspection coordination may be separate line items. HOA approval and county approval are separate processes. Confirm requirements with the county for your address, then identify who prepares, submits and pays for each item in the estimate.
Check the official Loudoun County deck guidance or Fairfax County permit requirements for the property's jurisdiction.
How long does a composite deck project take?
Separate the construction period from the full project schedule. Design decisions, HOA review, permit review, materials, inspections and weather can each affect the start or completion date. Request a schedule showing those dependencies. A contractor should confirm a construction window after the scope and required approvals are clear.
Financing your composite deck
Financing options may be available for eligible projects, subject to approval and provider terms. Establish the written project scope first. Review the amount financed, APR, term, fees and total repayment before choosing a payment option.
Composite deck cost questions
How much does a 20x20 composite deck cost in Northern Virginia?
A 20x20 deck is 400 square feet. With Trex Transcend, one stair flight and composite railings selected, the calculator on this page produces $28,125 - $51,300. Those are preset modeling assumptions, not a completed-project price. Confirm demolition, framing, footings, permits, electrical work and cleanup in a property-specific estimate.
Does the calculator include railings and stairs?
Only when you select those add-ons. The size table below shows both the base scenario and the scenario with one stair flight and composite railings. Neither output verifies the length of your railing, stair height, existing structure or local permit fees. Those details need an itemized estimate.
Is a manufacturer material estimate the same as an installed quote?
No. A material estimate covers its listed products and assumptions. The Trex material calculator explicitly separates labor. An installed proposal should also identify demolition, structure, labor, stairs, railings, permits and cleanup as applicable. Compare the included quantities and exclusions before comparing the totals.
Can the existing frame reduce the cost?
Reusing a suitable frame can reduce the work compared with rebuilding it, but eligibility depends on an inspection and the proposed design. New decking does not correct deteriorated framing, inadequate connections or unsuitable joist spacing. Ask for separate resurfacing and replacement scopes when both remain feasible after evaluation.
Can you pressure wash composite decking?
Follow the care guide for the exact product and generation. Trex and TimberTech publish different limits and cleaning procedures; one pressure setting is not a universal rule. Check the approved cleaner, nozzle, distance and technique before starting. Use the manufacturer care links below rather than treating warranty length as a cleaning instruction.
Does composite decking guarantee a return at resale?
No. Resale recovery depends on the property, condition, market and buyer preferences. A manufacturer warranty is also not a guarantee of resale value or the service life of the entire structure. Choose a documented scope you can afford and evaluate maintenance and daily use alongside potential resale appeal.
Product care sources: Trex care and cleaning and TimberTech care and cleaning. References checked September 13, 2026.
Plan your Northern Virginia project
Loudoun Decks works with homeowners in Ashburn, Leesburg, Sterling, Fairfax, Reston, McLean and surrounding Northern Virginia communities. Include your ZIP code, approximate deck size, photos you can take safely, and whether you want a new deck, replacement or resurfacing when you request an estimate. Confirm scheduling and service availability for your address with the team.
Continue with resurfacing vs replacement, railings, stairs and lighting, or stair planning.
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