# How do I estimate deck material cost?



## Movingshrub (Jun 12, 2017)

Has anyone built their own deck?

The XO wants me to build one. I'm torn on materials between pressure treated pine, which would be painted, cedar (clear coat or light stain), or a composite decking. All three options would involve pressure treated pine for the dimensional lumber; Exceptions might apply to posts for the cedar option depending on how the railing is done.

Does anyone know how to price a project like this? Board foot? Square foot? I'm looking at either a between 300 sqft (15'x20') and 450sqft (15'x30'), depending on the layout my wife decides on.

Just to be clear, I'm looking for a way to estimate the cost of materials. The labor cost will be zero. Thank you


----------



## gijoe4500 (Mar 17, 2017)

When I built my mom's deck, once she gave me the rough dimensions she wanted, I just sketched up how I would build the deck. Drawing on a piece of paper each board. From there, I made a parts list and looked up pricing on Home Depot's website.

Definitely not necessarily the best way, but at the time, it was the easiest way for me.


----------



## ABC123 (Jul 14, 2017)

Menards has a deck estimator app on its website


----------



## Colonel K0rn (Jul 4, 2017)

I'm interested in this also. Wife wants a deck for the pool.


----------



## Cory (Aug 23, 2017)

There are a lot of variables, draw it up and go to the store and check the prices. Decks.com has some caculators but not sure how accurate they are as far as pricing goes. I am currently building an 8x7 next to our pool with a 6x7 pad coming off our original deck. I have spent $1400 including nails, nuts bolts and washers for railing post, all standard pine, 6x6 support post's, no steps, solar LED post caps, and solid railing instead of pickets.


----------



## Reel Low Dad (Jun 1, 2017)

Lowe's also has (or had when I built mine) a deck designer. It will give you a full on materials list that you can take to the counter to order. I cant remember if it had pricing on it as well but that can be pulled off their website. The only thing I would do is if you went with composite decking to space your joists no more than 16" O.C. and I would almost go 12" O.C. due to sagging I have witnessed. This was on older composite so maybe it has improved some.


----------



## Movingshrub (Jun 12, 2017)

I'll report back if I find anything that works. I seem to get widely different estimates from each website, with no indication on what year was used to price the materials.


----------



## Cory (Aug 23, 2017)

Movingshrub said:


> I'll report back if I find anything that works. I seem to get widely different estimates from each website, with no indication on what year was used to price the materials.


The problem is that there are different grades of lumber. The structural lumber like support post, girders, joist are fairly standard. But there are so many different decking and railing options that it make it's difficult to make an estimate without knowing what you want and need. There are 2 grades of pressure treated pine but also other wood types, then throw in composite decking it adds a whole other element and the cost is substantially more. Steps can very greatly depending on how high you need to go or if you want to get precut stringers. 2x6's for stair treads or 5/4 boards will dictate how many stringers you need as well. You can span stingers with 2x6 treads much further than you can with composit 5/4 treads.

If you want and accurate estimate you really need to sketch it up and decide on finish materials so you can make a cut list and price it out.


----------



## Movingshrub (Jun 12, 2017)

Makes sense. I am really trying to figure out, roughly to the nearest thousand, how much I should expect for my decking materials.

I'm trying to build either 15'x20' or 15'x'30 rectangle deck, with four steps to get off the deck.

I totally get the different grade of materials. However, just to illustrate the challenge. I went to Trex's website and got an estimate for the smaller size deck of between $4800-$6700 in materials. Another website said $14,000 and another said $1800-$2700 (which seems WAY too low)

A range of $1800 to $14,000 just seems way too wide to provide any kind of useful estimate.

I'm in a position where I want to do cedar. If cedar is more expensive than composite, the XO is going to veto it. If composite and/or cedar are cost prohibitive, than pine it is. I would think I could figure out as a ball park, which each of those are going to cost me cause the structural lumber should be the same for all three.


----------



## kevreh (Apr 3, 2018)

I've built a number of decks. Some tips;

- Visit a couple lumber yards, or find the best one near you. They'll have the better quality materials you want whether its the PT framing lumber or composite decking. Don't by the inferior lumber and trex from Home Depot. 
- Are you planning it yourself? You'll need to do calculations on spans, framing, and footers. Number of footers dicates spans, span lengths a function of lumber size (eg. 2x8 vs 2x10).
- Lumber comes in certain lenghts like 8',10', 12', 14', 16'. Not all dimensions come in all lengths. If you plan a 15' deck you'll be wasting lumber (cutting 1' off a 16'). Not a huge deal, but in that example why not plan on a 16' deck?
- Highly recommend composite. Again, what does the local lumber yard carry? Once you find out, check the manufacturer specs. Do they want 12" or 16" on center? etc.... 
- ^^^ Composite is so much better than wood. I love cedar but it will still require staining. Composite will never crack, splinter, etc. While composite like Trex and Azek are more now, you have to factor the cost to stain it, then clean and re-stain every few years. The more I spent on Trex 10 years ago is a distant memory, but the fact I dont have to maintain it is a nice dividend.

In terms of cost, just build a spreadsheet. Do your plan, then plug in the numbers with the costs. Spreadsheet should have the # of joists, concrete cost for footers, hardware costs (screws, nails, joist hangers), decking costs, railing costs.

Are you planning and building yourself? Decks can be spendy. After you do your research, not that bad. But there's a lot of details.

Hope this helps, let me know if you have more questions.


----------



## Guest (May 29, 2018)

Movingshrub said:


> Makes sense. I am really trying to figure out, roughly to the nearest thousand, how much I should expect for my decking materials.
> 
> I'm trying to build either 15'x20' or 15'x'30 rectangle deck, with four steps to get off the deck.
> 
> ...


I'm not a deck builder but cedar is really high here. I just build a raised garden bed 5'x10' and to do what I wanted in cedar was almost 450$.
I can't imagine what a deck would be but I was told it will last longer than me. I settle for Douglas fir and pine and will see how it goes. I'm following along cause I want to screen in my porch some day


----------



## Movingshrub (Jun 12, 2017)

kevreh said:


> I've built a number of decks. Some tips;
> 
> - Visit a couple lumber yards, or find the best one near you. They'll have the better quality materials you want whether its the PT framing lumber or composite decking. Don't by the inferior lumber and trex from Home Depot.
> - Are you planning it yourself? You'll need to do calculations on spans, framing, and footers. Number of footers dicates spans, span lengths a function of lumber size (eg. 2x8 vs 2x10).
> ...


I had some time to read while hanging out with my wife and newborn in the hospital.

I am looking to do 16' by 26 or 28'. My concern is that I may need to do freestanding since I have brick-veneer exterior. I'm struggling to figure out the spacing of the support posts, relative to the size of the dimensional lumber.

Assuming the deck stuck out 16' from the house, would I be able to get away with 2x10x16 at 12"OC or 2x12x16 at 16" OC with only a post at the house and another 16' away (at the corner)? I understand the requirements are different for the 28' span, in terms of the beam. I'm trying to find the balance between number and spacing of posts (planning to do 6x6), the size of the dimensional lumber required, and the size requirement of the footer.


----------



## diy_darryl (May 15, 2018)

I built my 30'x30' deck and Pergola 10 years ago and I drew everything to scale on graph paper which helped me calculate materials and identify a few issues before I started. That might be the hard way but it worked for me. I went with 16" centers. pressure treated frame of course and Cedar for everything else. I did a better job than I could have ever got from a contractor (in my experience), got the satisfaction of doing it myself and saved a ton of money. I got bids of $20K but did it myself for $10K in materials. That was 10 years ago so no idea what it would cost now?

I would say that Pressure treated is by far the cheapest, Cedar is quite a bit more but very NICE and COMPOSITES are BY FAR the MOST expensive option and there are tons of bad reviews on mold/mildew, cracking, warping not to mention that you likely need a substructure with 12"o.c. joists to support the flimsy pvc material.

You are far better off going to your local lumberyard! They can help you out with figuring materials, especially with a drawing, make suggestions, deliver your lumber to the jobsite (usually free for a big enough job) and you get BETTER LUMBER than the box stores.

Here is a pic I dug up from when our deck was first completed before any stain or other landscaping etc., it still looks great. There is now an inground pool to the left and aluminum fencing enclosing the whole area in, furnishings etc.....

Good Luck.


----------



## Movingshrub (Jun 12, 2017)

@diy_darryl My project will involve being elevated, so rails and stairs are a requirement. I'm actually kind of adverse to composite based on the aesthetics. I like the way wood looks. I'm planning on PT pine for the framing, and then evaluating cypress, ipe, cedar, and redwood for the decking. However, depending on the differences in installation, maintenance, and cost, composite and PT pine decking are all considerations.


----------



## diy_darryl (May 15, 2018)

The lumber yard can help you out with allowable spans. I surely don't remember now but I did a LOT of research before I built. It seems like I dug 26-28 post holes total for my project and that part of it SUCKED!


----------



## kevreh (Apr 3, 2018)

Movingshrub said:


> I had some time to read while hanging out with my wife and newborn in the hospital.
> 
> I am looking to do 16' by 26 or 28'. My concern is that I may need to do freestanding since I have brick-veneer exterior. I'm struggling to figure out the spacing of the support posts, relative to the size of the dimensional lumber.
> 
> Assuming the deck stuck out 16' from the house, would I be able to get away with 2x10x16 at 12"OC or 2x12x16 at 16" OC with only a post at the house and another 16' away (at the corner)? I understand the requirements are different for the 28' span, in terms of the beam. I'm trying to find the balance between number and spacing of posts (planning to do 6x6), the size of the dimensional lumber required, and the size requirement of the footer.


Its' outside the scope of a discussion like this for someone to give you specific answers to what is allowable in terms of joist sizes, spans, OC spacing, etc... If your going to do this by yourself you need to do the calculations. Also, you should draw up some basic plans and get them approved by your county and get a permit. If not, you may run into non-compliance issues when you sell someday. Even if you don't get a permit, you need to at least build to code.

This document has some tables showing minimum allowances for sizing and spacing; https://www.fairfaxcounty.gov/landdevelopment/sites/landdevelopment/files/assets/documents/pdf/publications/deck-details.pdf

Check with you county to see if they have a similar document. If not, here's a similar document based on the IRC (International residential Code); http://www.awc.org/pdf/codes-standards/publications/dca/AWC-DCA62012-DeckGuide-1405.pdf


----------



## kevreh (Apr 3, 2018)

diy_darryl said:


> I built my 30'x30' deck and Pergola 10 years ago and I drew everything to scale on graph paper which helped me calculate materials and identify a few issues before I started. That might be the hard way but it worked for me. ...


That is a great way, to use graph paper. Doing a simple plan allows you to see everything before you start, not to mention the plan will act as a guide so you can order the right materials.



> You are far better off going to your local lumberyard! They can help you out with figuring materials, especially with a drawing, make suggestions, deliver your lumber to the jobsite (usually free for a big enough job) and you get BETTER LUMBER than the box stores.
> 
> Here is a pic I dug up from when our deck was first completed before any stain or other landscaping etc., it still looks great. There is now an inground pool to the left and aluminum fencing enclosing the whole area in, furnishings etc.....


Key here is to show up with a plan, even if drawn on graph paper with a ruler. Make sure your plan shows dimensions, spacing, joist sizes, etc.


----------



## Movingshrub (Jun 12, 2017)

End result. It only took me a year.


----------



## TN Hawkeye (May 7, 2018)

Movingshrub said:


> End result. It only took me a year.


That's a nice looking deck. I'm sure all the more rewarding since you built it your self. Great job.


----------



## Ware (Jan 28, 2017)

Movingshrub said:


> End result. It only took me a year.


Nice work! Looks great!


----------



## Movingshrub (Jun 12, 2017)

@Ware @TN Hawkeye Thanks!

The total deck was approx 16'x28'.

I ended up framing the thing as free standing using drop beam construction.

My plan was 15ea 2'x'2'x2' footers. I found the sewer main line when digging one of the footers, and ended up omitting that footer and building a more robust beam to account for the increased span. In each footing, I applied small aggregate, compacted it, installed 5/8" rebar on rebar stands, and then mixed and poured concrete. I made the mistake of mixing about 20 bags by hand. After that, I rented a mixed machine and knocked out 80 bags in an afternoon/next morning.

As a result, all of the beams were three plies of 2x10s, woven together so all seams had bearing upon the 6x6 posts. I used Simpson Strong Tie elevated post bases (ABA66Z) anchored into the concrete using HDG threaded rod secured to the concrete via SST AT-XP epoxy. I used SST post caps to connect the beams to the posts. Once the beams were all installed, I ran 16' 2x10 joists over all of the beams. I installed the house side rim joist and then pushed the entire framed 16'x28' joist assembly back into contact with the house. I did install vinyl flashing on the house-side rim joist prior to pushing it into position. I then installed 2x10 blocking between the joists over each beam. I used Grace Vycor flashing tape over all of the beams, joists, and blocking. To attach the joists to the beams, I installed SST H1Z or H2.5AZ hurricane ties at each joist, on each beam. Furthermore on the framing, I did double 2x10s for the outside joists and rim joists. Lastly, due to the deck being free standing, I installed knee joists on the outer posts (post to beam) and installed diagonal blocking via 2x6's ran along the bottom of the joists (it was routed such that at looks like a chevron shape from above).

Once complete with the framing, I installed 6x6" ipe posts using 1/2" carriage bolts. The carriage bolts were also fed through SST deck tension ties so as to help preventing failure of the post if pushed at the top edge, seeing as it's a giant lever. On the posts I routed at 3/8" deep, 1.5" tall, rabbet at the top and an equivalent dado 32" down to serve as notches for the railing assembly. I then built railing assembles consisting of 2x2" ipe balusters, and 2x4" ipe top and bottom railing. Each baluster was attached with SST #9 Stainless Steel trim head screws. Each screw required pre-drilling. My best route was to have a cobalt drill bit to pre drill, another drill with a counter sink, and then an impact drive to sink the screw. 
I attached the railing assembly to the post via 2ea 3" #10 stainless steel screws on each end of the railing and then 2ea #9 2.5" trim screws on the bottom railing. I tied this all together visually with a 5x4"x6" ipe top rail, secured from below by trim head screws. I used miter joints for the railing corners and scarf joints for the long runs where I mated boards rather than using butt joints.

On the decking, I used 1"x6' ipe decking boards. Everything required pre drilling. I had the same drill bit, counter sink, impact driver setup. I used over 2,000 screws for just the decking boards, also SST #9 304 stainless trim head screws. I hit all of the fasteners for the railing but okay with face screwing the decking boards.

I went 1"x6' ipe decking boards to serve as fascia to conceal the pine 2x10 framing and then 3/4" pine lattice as skirting.

To finish it off, I used Penofin brown label hardward formual rosewood oil in transparent tone to protect the ipe. I used Woodlife copper coat wood preservative on all the cut ends of the PT pine. I tried to be as conscious as possible about corrosion in terms of using either SS or HDG fasteners, and flashing tape where appropriate. I wanted to avoid creating additional penetrations into the brick facade of house, hence the freestanding construction. I ended up using solid brass handrail brackets, where I stripped the lacquer so they will patina.

I had help from a neighbor on cutting the stair stringers and my wife on moving gravel for the footers; everything else was a one man job.

Lessons learned - Everything takes way longer than you expect. I was surprised I only broke three drill bits on the whole project, all at the end when I was getting in hurry. A palm nailer was super useful. Getting a framing nailer in at the correct angle to secure blocking when joists are 12" OC is not easy. Oil the ipe as soon as you can once its outside. I almost wish I had oiled immediately upon/during/prior to installation.


----------

