Cedar vs Pressure Treated Wood

Cedar and pressure treated (PT) lumber are the two most common choices for outdoor wood projects. Both resist rot and insects — but through very different mechanisms and at different price points.

Quick comparison

Factor	Cedar	Pressure Treated (PT)
Cost (2×6×16)	$18–$35	$10–$18
Lifespan (above ground)	20–40 years	40+ years
Ground contact rated	No	Yes (UC4 rating)
Appearance	Natural wood grain, reddish-brown	Green/brown tint, may have texture marks
Workability	Easy — lightweight, sharp edges	Good — heavier, splits more if nailed when wet
Chemical treatment	None — natural oils	ACQ, MCA, or CA-C preservatives
Splinter risk	Low	Higher when old/weathered
Maintenance	Stain every 2–3 years	Can go natural; staining extends life
Smell	Pleasant cedar aroma	Chemical odor (fades in weeks)

Cost for a 12×16 ft deck

Component	All Cedar	PT Structure + Cedar Surface	All PT
Joists/beams (PT structure)	$800	$600	$600
Decking boards	$1,800 (cedar)	$1,800 (cedar)	$900 (PT)
Posts/footings	$300	$200 (PT)	$200
Total materials	~$2,900	~$2,600	~$1,700

Prices vary by region and lumber market conditions. PT structure + cedar surface is the most popular professional choice.

Where each is the right choice

Use cedar for:

Deck surface boards — looks better, feels better underfoot (PT gets rough as it ages)
Fence pickets and rails — where appearance matters and ground contact is minimal
Pergola rafters and beams — where aesthetics are important
Raised garden beds — cedar is safe for vegetables; some PT chemicals aren’t recommended
Interior woodworking — cedar is a great choice for closet lining and interior projects

Use pressure treated for:

Deck posts — PT required by code for any post in or near ground
Deck joists and beams — PT is code-standard for deck framing
Ground-contact applications — fencing posts, bottom plates, landscape timbers
Fence posts — anything buried in the ground
Structural framing where appearances don’t matter

Finishing and maintenance

Cedar:

New cedar can be stained or sealed immediately
Apply oil-based semi-transparent stain for the longest protection
Re-stain every 2–3 years for maintained appearance
If left unfinished, cedar turns gray within 1–2 seasons (silver-gray look is popular)

Pressure treated:

New PT lumber needs to dry 3–6 months before staining (high moisture content)
Apply water-repellent deck sealer once dry
Re-seal every 2–3 years to prevent cracking and splinters
Do not use oil-based stains on freshly treated wood — wait for the PT to dry

Health and safety

Modern pressure treated lumber uses ACQ (Alkaline Copper Quaternary), MCA, or CA-C treatments — these replaced the older arsenic-based CCA treatment (banned for residential use in 2004). Modern PT is safe for residential use including:

✅ Decks and play sets
✅ Landscaping timbers
✅ Fence posts

Not recommended for direct food contact: some experts still recommend cedar or untreated wood for raised vegetable beds, though modern ACQ treatment is considered low-risk.

Frequently Asked Questions

Is cedar or pressure treated wood better for a deck?

Cedar is the premium choice for visible deck boards — it looks better, stays cooler underfoot, and is easier to work with. Pressure treated lumber is standard for structural members (joists, posts, beams) because it's cheaper and code-required for ground contact. Many builders use PT for structure and cedar for the deck surface.

How long does cedar wood last outdoors?

Properly maintained cedar lasts 20–40 years. Unfinished cedar turns gray within 1–3 years (attractive to some) and lasts 15–25 years. With stain or sealant applied every 2–3 years, cedar can last 30–40 years. Cedar heartwood has natural oils that resist rot and insects.

How long does pressure treated wood last?

Modern ACQ pressure treated lumber is rated for 40+ years above ground and 30+ years for ground contact. Older CCA-treated lumber (pre-2004) typically lasted 50+ years. PT wood in continuous ground contact will eventually rot even with treatment — use concrete footings wherever possible.

Can I use cedar in ground contact?

Cedar heartwood is naturally rot-resistant but is not rated for ground contact by building codes. For posts and anything buried or touching concrete, use pressure treated lumber rated for ground contact (UC4A or UC4B). Save cedar for above-ground applications.

Which is cheaper — cedar or pressure treated?

Pressure treated lumber is typically 30–50% cheaper than cedar for the same dimensions. A 2×6×16 PT board costs $10–$18; the same in cedar costs $18–$35. For a full deck, PT structure + cedar decking often costs the same or slightly more than all-PT, but gives a much better finish.