Converting a house to a garage?

[gryzynx]

Hi,

Newbie to this forum. Searched this topic, but looks like I'm trying something new.

Seems to be lots of info on sacrificing your garage for the sake of additional living space, but I have the opportunity of converting a small house into a garage. I purchased a property with an old single story home, maybe 600 sq. ft and probably 75 years old or more. Property is currently zoned commercial and the local building authority is willing to consider what I may put forward. The objective is to create some low cost shop and storage space for my toys. The basic wood frame structure and concrete beam foundation are sound. Basement is a dirt dugout. Home has not been lived in for some time. My plan is to gut the interior, add an overhead door, and use metal siding to refurb the exterior. The floor structure is my problem. Of course, I want to exchange the wooden floor for something fireproof. My thought is to remove the floor and joists, refasten the walls to the foundation, fill the dugout basement with gravel and pour a concrete slab within the existing foundation. What concerns me is how to keep the walls in place after the floor joists have been removed. Will simply using a new bottom plate and concrete nails into the existing foundation work? How do I deal with the gap that the old floor joists would represent? Will the beam foundation keep the walls from moving horizontally? I've got some ideas as to how ai'll accomplish all this, but I was wondering if anyone has had experience with this type of a project.

 

[rusty1]

Funny that you bring this up as I'm considering doing the same thing. I was going to take out the walls, the wood floor and joists and fill the shallow dirt basement it now has with gravel and use it just for cold storage. Maybe in the future I'd cement the floor.

The house I'm looking at has old limestone foundation with the wall timbers sitting on top of that, it's not really anchored to the foundatin.
You could drill holes in some of the wall studs and insert rebar thru tnem and bend them down into the poured cement floor, that would secure the walls to the slab. They do this when pouring cement floors in pole buildings. (rebar thru the poles into the slab)
I wouldn't really worry about it moving much if it's been there that long.

 

[gryzynx]

That's pretty much what I hope will happen. That foundation has been in the ground for years and it's probably packed in as good as you can get. Soil tends to be light around here, but the building is relatively small and the possibility for horizontal movement seems minor. I like the idea about the rebar loops thru the wall studs. I was also thinking about building a short pony wall to take up the space left by the removal of the floor joists and power nailing that to the foundation. Might find out how hard that old concrete can get! I'm also thinking that a fairly wide sill, say 2X8 double plate would add a lot of stiffness to the bottom edge of the wall and a second set of 2X4 wall studs offset from the originals could make a 7" wall with no studs contacting both the interior and exterior surfaces. That should make for extremely good insulation which would be a real bonus on those cold winter days.

 

[rusty1]

...Your ideas sound good to me, and especially on the thicker wall insulation, that building would be a lot warmer even without heat.
The old house I'm lookin at has the walls built on timbers that just sit on top of the old limestone foundation, they aren't even anchored to it. I think the floor joists tie into the wall studs and drop down inside the foundation some so that kept it from shifting sideaways any.
Since it's gonna have a filled in basement, I thot I'd just plant a 6 -8 4x4's in the corners and along the walls and anchor those to the wall studs, burying about 2 feet and let them stick up about 6 feet higher than the foundation. It couldn't go anywhere then.
Is your house a 2 story? The one I'm lookin at is, I was gonna cut an access hole so I could store stuff in the stairs, or just build a new stairway wide enuf to get stuff up there easily.

 

[v8garage]

Other than the foundation the next thing to look at is if you are going to be taking out any load bearing walls. If so you need to put in some good beams to carry the load. Sound like a great project, good luck with it.

 

[InPrimer]

My 2c worth, being a ex northener, I would consider some type of floor vapor barrier or some rigid foam to keep the moisture from penetrating. If you work there in winter its downright pleasent for the floor to be about 65 deg.There are some floor type piping (concrete) heaters that are reasonably priced and probably cheaper to run than a typical gas/oil furnace hope this will make you think about it...

 

[gryzynx]

Single story house, but there seems to be an attic access from the outside. These old houses don't have prefab roof trusses, which makes for more open space, but, yes, load bearing interior walls can be an issue. House is about 25X25 with the interior divided into 4 rooms. I'm going to fabricate a header and posts for the overhead door and I'll tie in a 4 ply 2X10 beam along the center of the roof. Should be able to span 25' without any interior posts,(I hope). We seem to be over the worst of the cold weather this year and I should be able to get in for some exploratory demolition within a few weeks. Planning is going to be the fun part! Property is located on the edge of town, so one of the functions this will serve is a headquarters for snowmobiling. Town has a bylaw banning snowmobile use within city limits, but all I have to do is shoot across the road and I,m on the trails. Also have 50'X150' property with this, so I can have outdoor storage for seasonal stuff like boats and campers. Planning for workshop space inside for mechanical and woodworking. Dreams are cheap, but the budget may limit me. I'm hoping I can salvage the floor joists for materials. I'll post some progress reports as I go along.

 

[gryzynx]

My 2c worth, being a ex northener, I would consider some type of floor vapor barrier or some rigid foam to keep the moisture from penetrating. If you work there in winter its downright pleasent for the floor to be about 65 deg.There are some floor type piping (concrete) heaters that are reasonably priced and probably cheaper to run than a typical gas/oil furnace hope this will make you think about it...

I've seen this type of heating out here a lot. sure is nice to not have to lie on a cold concrete floor! I've even seen systems cobbled together from black PVC and an old water heater. I think the packaged systems would be a lot less hassle and might even work better. That rigid foam underneath the pad would be a big help as well. I'm considering pouring the floor below the top of the foundation to add a little headroom as well as keeping water, sparks from welding/grinding, etc away fromm the wall sill. Not sure what I'll do about the rise from the floor to the foundation as far as overhead door access goes. Has anyone had any luck with cutting down a concrete beam in such a situation?

 

[BooUrns!]

I can appreciate your efforts to 'recycle' an old space and give it new life but what you propose is too large and costly of a modification to justify the risk. There are all sorts of problems that might arise during your renovation that could prevent you from being able to safely use the structure.

The foundation you're thinking of using is to old to incorporate into a new build. A new garage package would probably cost less and be structurally sound.

 

[rusty1]

I can appreciate your efforts to 'recycle' an old space and give it new life but what you propose is too large and costly of a modification to justify the risk. There are all sorts of problems that might arise during your renovation that could prevent you from being able to safely use the structure.

The foundation you're thinking of using is to old to incorporate into a new build. A new garage package would probably cost less and be structurally sound.

...I don't think it'd be that big of deal, the one I'm thinking about I would leave the upstairs floor and install a few posts to replace the one supporting wall that I'd be removing. The whole thing is only 16x24 so it's not that huge of a structure. As far as garage doors, I'd only be installing 8 foot wide doors, so that wouldn't be difficult building a header for.

I've done simialar projects with my dad so I know it can be done reasonably and safely. Too many people now days tear anything old down instead of recycling things.

 

[gryzynx]

I'd have to agree that this is a pretty ambitious project, but I'd also disagree that a new package would be cheaper, or safer. Easier, yes, but I've had quotes for a 20X30 garage finished that reach to $30K. I figure I might be in the $5K to $10K range for what I propose to do. BooUrns, I see you're from Edmonton. You know as well as I do what the situation is around our neck of the woods regarding building trades. Even if I had the means to build new, I may be waiting a year or more for the contractor to show up! Still, you correctly point out that there are a lot of pitfalls associated with this, that's why I turned to this forum for help.

 

[BooUrns!]

Are you planning on using this as a garage or as a workshop? My understanding was that you wanted a floor that could take the weight of a vehicle.

If you're just trying to make the floor fire resistant, look into reinforcing the **** out of the basement and pour a reinforced slab on the original floor.

As for building trades, they are not as busy around here as they were in 2006. There are a lot of guys who have moved on due to lack of work. Lots of tools up for sale on the buysell etc. The renovation market is going to warm up soon though.

 

[kbs2244]

Some things to check:

First, the outside walls should be over the foundation walls.
So it shouldn't be me much of a problem supporting them when you take out the floor
joists.
The ends of the joists may go all the way to the outside of the foundation, with the walls resting on a platform formed by them and the sub floor.
Or the wall studs may come through the sub floor and rest on the sill plate directly.

Get down in the dirt with a good light and check to be sure.
You want to look real close for rot where the wood meets the rock.
While you are down there check for middle of the house support piers.
They will be under any load bearing walls upstairs.

From its size and age, it is almost certain that one of the walls is load bearing.
Most likely a long one right down the center of the house.
You will have to get into the attic to be sure of which one.
You will se the attic floor joists, which are the downstairs celing joists, meeting over the wall.
You will have to plan on replacing that wall with a beam.
To do this will have to break into the outside walls at the ends of this beam to put in supports.
A 25 foot long beam should be laminated wood or a steel "I" beam.
Or you can go with a center post and doubled 2x8'a.

Unless you go to doors on each side of these beam support pillars your big door will have to be crosswise to the beam.

I like your basic idea.
If you do it, the first thing to do is turn off the electric and water and the get a dumpster and tear out all the plaster and old wireing and pipes.
Including the celings.
This will give you a clear picture of how the strucure is put together.

I would say a deal breaker would be so much bad rot at the bottom of the walls that will mean a lot of scabbing on new wood, or the placement of the big doors in relationship to the central beam relates to the lot.

I wouldn’t worry too much if you need a center post.
Tons of guys have them.

 

[shocksystems]

How about some pictures?

Cheers!

Jim