Lean To Outdoor Space Next to Garage

I have similar but there is a wall 2m from the garage so I only needed the roof part. Closing in the side opposite the garage will make it a lot more usable. Make sure you manage the water runoff - a gutter and downpipe into a soakpit would be best.

Is that a vent for an oil/gas boiler. Just check the requirements for venting etc.

We have built something like this in September, it was at the back of our garage and it was to use it as a storage area, mainly for fire wood.

Ours is not as chunky as your chatGPT render

I don't have a more finished picture on my google photos for what ever reason

I think it works very well. Ours is North east facing and is not as dark as we thought it would. I do have lights installed in it for when needed.

Basic overview of what we did (only previously experience building a structure anything like this was a hen coop, so we don't really have a clue)

• 4x2 Wall plate on the garage
• Dug out holes where the posts were going and filled them with concrete. Used ground mounted post holders for the posts. Main goal was to keep the posts dry
• Posts are 4x3, local building supply place didn't have long enough 4x4.
• 4x2 plate (?) on the post side. notched into the posts
• Rafter are 4x2. Cut with birdmouth to sit on the two wall plates
• 3x2 perlins. Notched into the rafter. 3 of them. This is handy because you don't need your rafters and roof sheets to line up.
• 2 foot wide corrugated roof. We bought sheets the length so we didnt need to cut them (I think it was 8 foot but I can't remember). 2 foot wide is handy so you can lean over it to attach it down without needing to climb on top.

Things that are not ideal

• The fall is pretty minimal, its only 5% or something. Havent seen any practical issues with this. This was for height reasons, if we made the fall more, it would have been too low on the lower part. (the chatGPT render looks very low)
• Roof can have some condensation on the inside on cold days. (maybe would be better if fall was more)
• No gutters yet, but it just goes into a ditch at the moment

Things I would do differently

• Maybe would use 2 4x2 rather than a 4x3 if I couldnt get 4x4. Its very sheltered where it is so not worried about it. That's more of aesthics or for my own piece of mind, there has been no practical reason to want to do this (It's completely sturdy)
• I would just joist hangers on the garage side for sure. Birdsmouth cut added a lot of time. Toenailing the rafter meant we needed to leave hammer swinging room on top so couldn't put the wall plate as high as it could have gone.
• Notching the perlins out of a 4x2 is not the right thing to do. Rafters should maybe have been 6x2. Or better yet, just don't notch and put perlin on top. Notching also took a lot of time
• Would consider putting a felt lined sheet roof for the condensation, especially if I planned to spend any time out there.

A better look at the perlin and post notch

lunch on the job

re wall plate, I think we gave the dash few hits with the hammer along where the plate was going to take anything significant but really nothing major. I felt the wood would take some of the unevenness.

The wall plate was pre drilled and we only needed to worry about the two outside holes of each section being right. Once they were right and fixed, the wall plate worked as a guide for the other holes.

Flashing, no we didn't do anything. Originally was on our list when planning the job but I felt it was unnecessary when we got to it. Where the roof hits the wall is only a few inches below the eaves, and between the eaves and the gutter it's a foot in.

I guess in theory some splash could hit the roof and go up, but I don't think it would be anywhere near the amount of water that would be hitting the wall if the roof wasn't there. We so no evidence of water under the roof even when raining heavily

Edit : but just want to confirm, I don't really have a clue so I might be the best person to give advice!

Yeah if I was going longer I would try for something chunkier. I think my floor to soffit height was closer to 8 foot so you've alot more clearance than me!

My favourite outdoor wood for structures and vertical cladding is Siberian Larch. It's more durable than Douglas Fir although if you need really big dimensions (e.g. long, deep spans) Douglas Fir will give you those. DF has a colour that you'll either love or hate - it can look quite pinky until it fades.

That's a pity, not a great feeling to get mocked for wanting to try something!

Something like what I built probably looks more difficult that it is (and not doing birdsmouth and notching out the perlins would make it a lot easier). The hardest part is probably the design or more specifically picking the material or approaches to use, but you could always make a best effort of a plan and get somewhere like here to sanity check it for you.

From a skills point of view there really isn't too much to it. If you can cut wood, attach your posts to the ground and attach the wall plate to the wall, thats about it.

If a big project like this feels a bit too big, maybe try something smaller that has a lot of transferrable skills. Build your next gate rather than buying it, build a bike shelter or something to cover the bins etc

The other thing about the way we built ours was that we could have started smaller if we wanted to test the water. Ours is 4 ~2m bays, we could have built one bay to try it out, so we wouldn't have spent too much time and money if it didn't work out. So something like that is also an option if you don't want to take on the whole project at once.