Shed against brick - what about moisture?

[aluminum13]

Hi, first post. I'm in the process of clearing out my garage space to make it less for storage and more for projects. I've decided that I can clear out a lot of clutter (garden tools, pots, maybe a saw horse or two) by building a small shed outside against the garage wall.

Basic stuff. But I'm worried about the shed up against the brick. I rather not build onto (anchor) the brick wall, but instead having it be a freestanding structure with its own back wall.

Those skids on the ground would make the foundation. Left over from this project.

Quick and ugly sketch-up.

So if I make the back wall let's say plywood or OSB, how can I protect the brick from moisture damage? Tar paper? A housewrap product? Ideally the shed would be backed up against the wall as much as possible.

My goal is to be able to minimize the impact on the brick so if I had to move/tear down the shed, you'd never know it was there. And so I don't get condensation. Maybe just anchoring into the brick is my best bet, but I'd love to hear suggestions.

 

[timewarp]

I think you could leave a 1" airspace between the bricks and the back wall and at the top put a piece of flashing under the wooden siding on the house and out over the roofing on the shed, this way there is not a lot of moisture getting between the shed and house, you could even have the back of the shed recessed an inch and that way the side walls would actually be all the way against the brick but there would be an airspace behind the shed.

 

[aluminum13]

I was thinking about the gap, but I've heard amounts up to 6" are necessary for ventilation. I can't find much of anything confirm or deny this, despite this being what I'd imagine to be a somewhat common project. I rather not go out 6", 1" is fine.

But otherwise, a gap and exactly what you were talking about timewarp -flashing under the siding and to the roof of the shed, and some trim boards and caulking extending off the shed to the brick wall, while the area behind the wall is left untouched.

 

[mmhouse]

I agree with timewarp...proper flashing and an airspace between the two walls (possibly hidden) would be the solution most likely to avoid problems.

 

[ddawg16]

I can tell you from personal experience that you want to keep that gap sealed....otherwise, all sorts of creatures will start living in there....not to mention all the junk that collects....and then your back to the problem of no air circulation....just rats living in the space....and spiders....

Build the shed as if you were going to close in all sides but stop short of actually putting on the back wall...just have the studs. Then put flashing around all edges....the inside will be open so the brick can 'breath'.

 

[aluminum13]

I agree with timewarp...proper flashing and an airspace between the two walls (possibly hidden) would be the solution most likely to avoid problems.

I can tell you from personal experience that you want to keep that gap sealed....otherwise, all sorts of creatures will start living in there....not to mention all the junk that collects....and then your back to the problem of no air circulation....just rats living in the space....and spiders....

Build the shed as if you were going to close in all sides but stop short of actually putting on the back wall...just have the studs. Then put flashing around all edges....the inside will be open so the brick can 'breath'.

This brings up a good point. Critters will be able to dig under the skids and get into that gap. Would I have to use sealant on the walls (along the edges of the flashing)? Caulk (peelable, washable) is alright but thick black tar would be more of an issue.

 

[josall]

I like the idea of butting the final side trim boards against the brick but instead of chaulking why not use a 3/4 x 1/2 rubber weather stripe on the edge of that board then **** it up. If it was mine I would only build 3 sides (once you side and deck it it's not going anywhere) and put tapcons in 4-5 location up each side in the mortar to the peak, they can be removed and patched easily if needed.

 

[aluminum13]

Yeah, I think leaving out the back wall is the best bet.

I don't think weather strip would compress into the mortar joints in the brick - I did look at it at the store. Cool idea, though.

Yeah, a few tapcons or even concrete nails might make their way into the final design for extra strength, those would leave minimal damage.


Thanks for the help guys.

 

[GirlnAgarage]

I'll be doing about the same project as you. My neighbor mentioned using the wall of the house as the 4th. He's got sheds all over the place in his yard. Are you going to cover the ground underneath the shed at all? (I'm assuming you'll put your beams on blocks?). I read online in a build where weed paper was rolled out then gravel put down under the shed footprint. I guess that is suppose to keep that area from getting bugs and weeds.


Just thinking outloud. Weather will be turning hot soon so I better get on this. Keep us posted on your shed

 

[bczygan]

I have 8 sheds in my yard including one exactly as you show, except the 4th wall is just the existing brick one. It sits on a 4" conc. slab. The roof is properly flashed and counter flashed into the brick and the side walls caulked to the brick. It is an unconditioned space and humidity changes with the weather, so tools are at the mercy of that. If yours was properly sealed, insulated and had a complete vapor barrier, you could condition it by providing supply and return air registers to the adjacent conditioned space.

 

[aluminum13]

I'll be doing about the same project as you. My neighbor mentioned using the wall of the house as the 4th. He's got sheds all over the place in his yard. Are you going to cover the ground underneath the shed at all? (I'm assuming you'll put your beams on blocks?). I read online in a build where weed paper was rolled out then gravel put down under the shed footprint. I guess that is suppose to keep that area from getting bugs and weeds.


Just thinking outloud. Weather will be turning hot soon so I better get on this. Keep us posted on your shed

I was thinking about the landscape cloth.

Right now, the ground is 8 feet 3 inches to the siding. So if I want to fit in a 8 foot shed (back wall) with the roof, I'll have to trench down the foundation.

The plan is:

trench down
tamp
(landscape cloth...maybe)
gravel
concrete pavers/block
- repurpose those 4x6 beams. really I just want it to become my floor. paint them with copper green preservative on the bottoms/edges. not sure about the spacing. wrap edges with 2x4s.

Then build walls, I'm going with the no back wall plan, side with smart side, roof with felt/shingles, flash from under siding (back rot?) to roof, dunno about other edges (flash those as well...more rsrch needed). paint black and white to match house.

 

[aluminum13]

I have 8 sheds in my yard including one exactly as you show, except the 4th wall is just the existing brick one. It sits on a 4" conc. slab. The roof is properly flashed and counter flashed into the brick and the side walls caulked to the brick. It is an unconditioned space and humidity changes with the weather, so tools are at the mercy of that. If yours was properly sealed, insulated and had a complete vapor barrier, you could condition it by providing supply and return air registers to the adjacent conditioned space.

Sounds nice, but I'm not going through the process of conditioning it. Just tools like shovels, clay pots, maybe a mower.

I'm interested in those side walls against the brick. I know very little about flashing. That's my next area to research.

Edit:
8 sheds! How big is your yard?

 

[bczygan]

Sounds nice, but I'm not going through the process of conditioning it. Just tools like shovels, clay pots, maybe a mower.

I'm interested in those side walls against the brick. I know very little about flashing. That's my next area to research.

Edit:
8 sheds! How big is your yard?

Lot is 40x100

Have you checked your zoning?
If this is a temp. shed you may have to build independent of the main building and keep a certain distance away. What are your setbacks? If you attach to main building are permits required?
Walls butted to brick are not flashed, but rather, they are caulked.
Why no conc. slab? How will you ventilate? Don't forget a light and switch. Make sure you have a decent roof slope. Don't be afraid for roof to **** into lap siding. It's easier to flash and counter flash there.

 

[aluminum13]

Lot is 40x100

Have you checked your zoning?
If this is a temp. shed you may have to build independent of the main building and keep a certain distance away. What are your setbacks? If you attach to main building are permits required?
Walls butted to brick are not flashed, but rather, they are caulked.
Why no conc. slab? How will you ventilate? Don't forget a light and switch. Make sure you have a decent roof slope. Don't be afraid for roof to **** into lap siding. It's easier to flash and counter flash there.

I'm not worried about zoning. Technically any shed needs a permit, and if it's attached to the house, it's an addition. Uh huh. Nothing fancy, it's a place to keep shovels.

No concrete slab because I don't see a need to go through the labor, if I need to move it later I can, and I can get a result which will likely be satisfactory using plain old gravel and block. It's a place to keep shovels.

No lights, no electric. It's a place to keep shovels.

My goals:

- minimize/eliminate impact to house structure.
- have a good little place to keep some garden tools out of sight and dry
- have a structure that isn't exceedingly visually obtrusive.
- built to last 20 years or so. if it has to be moved or torn down if/when my family moves, then ok.

Ventilation via soffit overhangs, maybe cut out vents in the side walls.

Thinking of 4/12 or 6/12 roof slope. After a little research flashing into or behind the lap siding will be much easier then messing with the brick. Thanks for pointing that out.

 

[onemore]

I need to do the same to get the lawn and garden stuff out of the shop. Good luck

 

[aluminum13]

This seems like a common project that people want to do.

No grand promises here, I'm a busy guy ya know, but I'll keep doing updates with pictures. Maybe make a new thread out of it. If I do I'll post the link to it here for any of you guys who have subscribed.

 

[tcianci]

What are you guys smoking? just build the thing, leaving a gap between the shed and the house and forget about it. I have never seen so many moisture "experts" in one place! You must be moisture experts 'cause the majority of you are all wet.

 

[rburke65]

I agree.....sure am glad some of you folks don't work at NASA...we would still be looking at the moon. Bricks breathing? Rats? Spiders?

 

[aluminum13]

Credibility war imminent.

 

[aluminum13]

Look, if a guy tells me from personal experience that something doesn't work, I'll listen. I'm not so concerned about what is "proper", I just want something that works and that I can assure my family in good faith that it won't mess up the wall or cause mold problems, and ideally, won't leave marks/scars on the brick.

Save the machismo - what will work and why do you think that is the case?

 

[bczygan]

The one I built against the house without any house wrap, just OSB and vinyl siding with a shingle roof stays dry, but gets humid with the seasons. Tools will slowly rust. And with a bucket of fertilizer in there everything rusted in a heartbeat. Forget exactly what kind it was. Good to keep garden tools out of the rain though. Rakes, shovels, mower, etc. Put a regular HM door on it with a lockset. Anchored 2x4's to the brick by drilling for anchors in the mortar joints so if it is removed they can be grouted and not show. Flashing also sawcut and caulked in the mortar joint. Vinyl j-mold just pushed up against the brick and not even caulked. Never leaked. Easy to drill a hole in the brick joint and run some Romex through to get some light and a switch. Easy peasy.

 

[Dominico]

I'm thinking about doing the same sort of project only attached to the back of my current 24W x 26D garage. It would be 8 -9' wide x 24' deep. Not sure if I need to do a footer and block or just pour a slab? I need to do some research and get some quotes on the cost to see if it is feasible.

 

[aluminum13]

The one I built against the house without any house wrap, just OSB and vinyl siding with a shingle roof stays dry, but gets humid with the seasons. Tools will slowly rust. And with a bucket of fertilizer in there everything rusted in a heartbeat. Forget exactly what kind it was. Good to keep garden tools out of the rain though. Rakes, shovels, mower, etc. Put a regular HM door on it with a lockset. Anchored 2x4's to the brick by drilling for anchors in the mortar joints so if it is removed they can be grouted and not show. Flashing also sawcut and caulked in the mortar joint. Vinyl j-mold just pushed up against the brick and not even caulked. Never leaked. Easy to drill a hole in the brick joint and run some Romex through to get some light and a switch. Easy peasy.

You were scaring me off with all the "proper" talk, but I see there is method to your madness beyond "following the rules." And I like the practical advice about the fertilizer.

The thing about housewrap is this:
If I build right against the brick wall, depending on the season and relative temperatures of the garage/inside of the shed, I'm going to have a cold spot on one side of the brick. That cold spot is going form condensation - or at least in the humid Washington, DC area, lots of water vapor on that side of the brick. So if that cold spot is the inside of my shed, I wonder if the wrap on three sides will help handle that humidity issue, or would moisture just come through that back wall (via the garage), making the 3 sided solution not as effective.

The above is based only on my most basic understanding (or lack there-of) of the factors at play.

Again, having my shovels slowly rust won't keep me up at night, but now I'm curious. I like to know how things work.


And MAYBE to the light. I do want to re-do the wiring in my garage.

 

[aluminum13]

Update - Shed construction thread here: http://www.garagejournal.com/forum/showthread.php?t=104624