How to build an outhouse

Our most popular project, ever!

By Wayne LennoxWayne Lennox


Privy, john, biffy, crapper, backhouse, whatever you call it, the outhouse remains a common architectural feature on the cottage landscape.

Technically considered a Class 1 sewage treatment system by the Ontario Ministry of the Environment, outdoor facilities constitute the master ensuite for a surprising number of cottagers, or provide backup relief for countless others. My brother-in-law is among the latter; he has indoor plumbing but still maintains an outhouse up the hill from the cottage. It takes the pressure off the septic system, and is handy when you’re working outside – no need to take the old boots off, just head up to the backhouse.

According to the Ontario Building Code (OBC), structures under 108 square feet do not require a building permit. (An outhouse over 108 square feet would be quite the edifice – the one featured in the July/August 1999 issue of Cottage Life magazine measures under 20 square feet.) However, it’s a good idea to check with your municipality for local bylaws regarding outhouses. There are also specific OBC regulations regarding their placement and construction.

Click here to download the plan.

Building tips

  • Dig the hole first. (It’s been known to happen: An enthusiastic DIYer erects the structure, then can’t find a way to excavate the pit.)
  • Pressure-treated or creosoted timbers are the best material for the base of the structure; untreated hemlock or tamarack (also known as eastern larch) are also good choices for their natural ability to resist decay.
  • Use 6″ X 6″ timbers (minimum) to frame the hole. Half-lap corners are advisable.
  • If you use pressure-treated wood, remember to treat all cut ends with an appropriate preservative.
  • Avoid letting soil touch the floor frame.

Project toolbox

  • Shovel
  • Wheelbarrow
  • Pry bar
  • Rake
  • Tape measure
  • Circular or hand saw
  • Hammer
  • Rechargeable drill with appropriate driver bits
  • Jig saw
  • Utility knife or shingle knife
  • Level
  • Square
  • Sliding T-bevel

The article was originally published in July/August 1999


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Jun. 23, 2014

2:56 am

Spent the winter cutting all pieces to exact dimensions in my woodshop and hoped for the best when it was assembled at the site. I was pretty lucky with exception to getting the *^$*&% seat box top installed. Found my vent whirly on, used T&G for the door and siding, and found 18"X24" single-hung windows at Lowes hardware. I used metal roofing due to heavy snow loads. Now that I'm done, I don't have the heart to use it!


Oct. 30, 2012

9:51 pm

Hi, I commented earlier in October 2012. Finally figured out the dutch door instructions. Had to re-read it like 4 times. It all makes sense now though. The wording was what got me. My problem now is I am in Alberta and the pine cove siding that the plan suggests is not available here. TIM-BR-Mart says they don't carry it. Well what is that about. Not sure what I will do to replace 1/2 " x 6" siding that I can't seem to find. Might have to resort to 1/2 " plywood and paint her up. Good luck to everyone on this new issue


Oct. 11, 2012

12:52 pm

I bought my 4" whirlybird at "Acklands Grainger"- Industrial, Safety, & Fastener supply store for $60.00. Has anyone actually built the Dutch door? The measurements on the illustrations don't jive with the measurements in the written instructions. I plan on building this outhouse in the spring of 2013, and would rather not go with a standard door, but instructions for this Dutch door are very limited. Seems like a few illustrations and wrirren instructions have been left out. Looks to me like there is 1x1 trim on the outside of the finished/painted door, covering the ends of the 1x6 tongue and groove, yet this is not mentioned in the instructions.


Aug. 24, 2012

9:19 pm

The lights went on in our new outhouse. While at Costco recently we found battery operated LED puck lights. They come in a four pack with a remote (wireless) switch and are self adhesive so are very easy to install.

Jul. 4, 2012

8:47 am

I'm pretty sure when I read the comments a few months back that someone mentioned getting the $" whirly turbine on Hwy 11. Does anyone remember the name of the store? I saw the links but when you add on the shipping I might as well go pick it up. I'm half way through my outhouse project. The plans are great. making small modifications along the way. I made it slightly longer and put fixed glass windows on the back facing the forest. Screens will be on the side as per the plan. Very happy with the progress. Pictures for the gallery when I'm finished.


Jun. 11, 2012

12:30 pm

Thanks, Tena. Here's the link for anyone looking for the Amazon whirly vent:


Jun. 11, 2012

1:19 am

Hey if you need to purchase the whirly vent, has them for 37.00 and some change, better than the $60.00 the gentleman stated he had to pay;-)


May. 26, 2012

7:58 am

I built this outhouse last year. Instead of using a pit, I elected to put a composting toilet in it since I have a drilled well. I bought an old window from Highway Recyclers by Webers on Hwy 11 for five bucks and it does the trick for a window. Easy plans to follow and had it built in a day. Used plywood outside with battens which reduced costs. Installed metal roofing instead of shingles and white washed the interior. I built a plywood cover for the door cut outs to prevent snow getting into the structure in the winter months, since it faces the lake (view is fantastic!!). Used an air nailer and concur with previous comments that it saves time.


May. 17, 2012

10:31 am

I built the outhouse using concrete manhole rings for the pit. They were cheaper and much easier than constructing a pit wall with pressure treated material. Dug a 42" deep pit with a backhoe and then had the machine place the rings and backfill.


Sep. 21, 2011

9:26 am

4" whirlybird (turbine) vents available at


Sep. 20, 2011

12:43 pm

I am in the completion process for this project. Very well written and measurments are outstanding. A couple of pointers: - Follow the steps as laid out otherwise you could run into problems - I opted for smaller and fixed windows which is easy to alter but keep in mind as you locate the boxes for them that the roof overhang is actually quite low with a 45degree pitch. - Reasearch proper roofing techniques before you shingle - Getting that pit dug and walled is a challenge. I used a galvanized culvert coupler and bent it and it worked fine. - You have to look hard for whirly vent. only available scarcely at heating suppliers. - I may regret trying to make a ductch door work. I might advise full door option instead. Besides who wants to see you at work in there???? - Air nailers will save you a tonne of time.


Sep. 7, 2011

9:20 pm

i am in same boat! help. Tried TimbrMart MacTier, RONA and Home Depot. Blanks.


May. 30, 2011

8:03 pm

Building this now but can't find a 4" whirlybird vent recomended in the plan. Any suggestions of where to get one? We are in GTA cottage in Muskoka. Thanks

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