I’m super excited about this outdoor sofa! I based this build off of a pair of modern chairs that I built last year. This sofa only cost me $40 in lumber to build but looks like it cost way more! If you are wanting to build the same sofa, you will have to adjust your measurements based on the size of cushions you will be using.

TOOLS:
Drill/Driver
Kreg Jig
Miter Saw
Table Saw
Sander
Clamp

SUPPLIES:
(3)-outdoor cushions @21″D x 25″ W x 5″ T
Outdoor wood glue
Blue Kote 2 1/2″ pocket hole screws (2-50 count packs)
(4)-2x8x8
(5)-2x4x8
Stain
Sealer
Rags
Brush for sealer

Cut List-Arm Rest
(4)-1.5 x 1.5 x 29.5″ L-outer side pieces
(6)-1.5 x 1.5 x 24″ L-middle slats
(2)- 1.5 x 3.25 x 24″ L-larger bottom slats

Cut List-Seat Frame & Back Support
(2) 1.5 x 3.25 x 65.5″ L-seat frame front & back piece
(2) 1.5 x 2 x 24″ L- side seat frame supports
(3) 1.5 x 3.25 x 24″ L-middle seat frame supports
(5) 2 x 4 x 65.5″ L-seat slats
(2) 1.5 x 1.5 x 9.75″ L-middle feet
(3) 1.5 x 1.5 x 65.5″ L-back rest slats
*(3) 1.5 x 1.5 x 4″ L-supports for back rest (I did not add these but suggest you do for more support in the back rest. I would put them in center of the back slats, one between each slat).

STEP 1: BUILDING THE SIDES
I started off by ripping (cutting) down a 2x8x8 to get the pieces that will make up my arm rests.

I made all of my pocket holes using my pocket hole jig, making sure to place the pocket holes where they will not be easily seen. The three middle slats will have them on the bottom and the larger slats, I placed them on the inside.

After the pocket holes were made I did most of the sanding because I find it easier to do it now before everything is assembled and harder to reach. The first piece I attached was the larger bottom slat. This slat should sit 13″ from the bottom of the outer side pieces to the top of that slat. I attached it using outdoor wood glue and 2 1/2″ Blue Kote pocket hole screws

Once I attached the larger bottom slat, I then attached the top slat and then attached the two other slats leaving a 4″ space between each one.

Here is what the arm rests should look like completely assembled.

STEP 2:BUILDING THE SEAT BASE AND BACK REST

I laid my three cushions out and measured to see how long I needed to cut my front and back seat frame pieces.

I lined up the front and back pieces with the lower side slats and attached them.  

I spaced the three middle supports by first measuring the center of the seat frame. The center ended up being at 32.75″ and then I found the center of the support and attached the two together. I continued to evenly space the other two middle supports and attach those as well. I found it helpful to use scrap 2×4 as a guide to know how far down the support should sit on the front and back seat frame pieces.

 

I took the two 1.5 x 2 x 24″ L support pieces and attached those to the inside larger bottom slats of the arm rest, again using a scrap 2×4 as a guide to know how far down it needs to go. 

Next, I attached the three back slats. 

I decided to the sofa need more support and so I added two supports in the middle of the frame to the front and back of the seat frame pieces.

I used a pre-stain wood conditioner to help get a nice even stain.

The stain I chose to use was left over from a previous project. The color I went with is called Mixed Nuts.

I stained the five seat slats before I attached them to the top of the seat frame with the pocket hole screws.  I found it easier to get everything coated with stain and avoid drips by doing it this way. I did end up adding the seat slats before sealing the sofa and I didn’t measure the spacing just did it by eye. You won’t see these slats once the cushions are on so exact measurements were not important to me. 

I also added a whitewash stain on top of the first color I applied. I have done this technique multiple times and it always comes out nice, but for some strange reason it did not come out as planned. I normally apply the stain to a small section and then immediately wipe it off but it seemed to dry really fast this time and that made it difficult to wipe off, so the sofa turned out with more of a whitewash effect than I like. 

Once the stain was dry, I applied an indoor/outdoor urethane. I like this one because of it’s clear, non-yellowing finish and it cleans up easily with soap and water. 

Here is the finished sofa!