A Victoria's Cottage in Western Maine

Started by Jeff922, April 14, 2010, 10:14:50 AM

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small cabin dreamer

Jeff, I know your busy being a new dad and all (Congratulations!) but I had a question on where you learned or found info on how to frame your own slab foundation. I am in the Upper Peninsula of MI and there is apparently solid limestone down about 30 inches so most neighbors use slabs above grade, but I am having trouble finding info on just how to do it. I see that you built frames 17 inches high, and they dont appear to go below grade and have 2 inch foam under all of it. I probably cant afford the heated system (pex is cheap, but the rebar and tying). Any more detail on how thick, and the small gravel and how thick would be very helpful.

Jeff922

Hi there, I used the NAHB design guide:

http://www.toolbase.org/pdf/designguides/revisedFPSfguide.pdf


I sort of made up my own way of doing the form-work.  I rented a DVD from SmartFlix (I think it was this one:  http://smartflix.com/store/video/3838/The-HowTo-Guide-to-Building-a-Monolithic-Concrete-Slab) which was also very helpful.  After the concrete was poured, I backfilled the perimeter of the slab but left about 8" or so exposed above grade.  Even if you do not use radiant heat, you will still need wire-mesh and rebar to reinforce the concrete (concrete is actually pretty brittle).  I would urge you to at least put the tubing in because you only get one chance to do it.  I think I paid about $700 for just the tubing.  I'm going to pour another slab this spring for my barn and I'll put tubing in it even though I don't intend on having radiant heat right away (if ever?).  I just don't want to kick myself later.  The footers were about 12" wide and the slab was about 6" thick (although it really only needed to be about 4").  The interior of the formwork was backfilled with locally available riverbed gravel. I think the largest stones were about an inch.  Whatever is local is the cheapest so long as it drains well and is reasonably dry when you pour concrete it should work just fine.  A FPSF foundation could get quite expensive if the soil conditions are poor (i.e. damp, poorly draining, clay).  The wetter the soil the more insulation you will need.  I only needed 2" because I'm on sandy soil.  I think I paid about $1200 for all the rigid insulation.  But I designed my foundation to go unheated if need be.  If your home will always be heated, you won't need as much insulation in the interior (the design guide explains this).  By the way, my dad is Michigan Tech Alumni, are you near there?
"They don't grow trees so close together that you can't ski between them"


small cabin dreamer

thankyou, I have very hard clay, and then limestone underneath that so it drains very poorly. I will rent the dvd to see what it says. Do you you have footers that went below grade at the edges? Also that much rebar is necessary to do it properly? I will probably see that in the video. So I will have to build up the center with the gravel just like I see you did. No we are not near Michigan Tech, sorry.

Jeff922

The footers were completely exposed and above grade immediately after the pour - the entire monolithic slab sits on top of the rigid insulation.  After the form-boards were removed, I backfilled over the perimeter insulation and up the edge of the footer until there was only about 8" of the side of the slab exposed above grade.  There really isn't that much rebar - just two courses in the footer trench and then the entire interior is covered with 6x6 wire mesh.  Does your lot slope at all?  You will want to address drainage any way possible.  There are two things needed to create a heave that could damage you foundation or home:  1) below freezing temps 2) water.  So you need to address freezing temps (either with rigid insulation or by excavation below frost-line)  or by addressing the issue of soil moisture content (good soil, good drainage).  Most likely you will need to do some combination of the two in order to meet the specifications of the design guide.  Also, with your soil situation, are you going to have a septic system?  Will this ground perc? 
"They don't grow trees so close together that you can't ski between them"

small cabin dreamer

well the area is hard clay, and then limestone on lake Huron. it is relatively flat, no slope. It does not perk so raised pressure mound is required. I can only go down about 30 inches to the limestone rock. So i am wondering if I can dig down to this limestone and pour my slab and footing or just put it on top of the existing clay. Probably smarter to remove the clay and put it on top of the limestone. then slope the ground away from the foundation. So what looks like rebar is the 6x6 mesh? And the footings are the 17 inch sides correct you used?


small cabin dreamer

yeah, I looked at the forms again and your in Maine (lots of snow and cold) and you didnt did down below the frost line. Does the 2 inch insulation foam help, I will use that too?

Jeff922

Check out that NAHB design guide - it's a little tricky at first but it's worth sitting down and doing the math.  If you can get down to the limestone in less than 4' it's probably worth doing.  It would be very solid and you would save some money by not doing a full FPSF (rigid insulation is very expensive).  My monolithic slab is basically just floating in top of a layer of 2" rigid insulation which is on top of sandy soil (you are correct, my foundation does not extend below frost line) and where I live is crazy cold (I think it's like 9700 heating degree days on ave.)  There has been no signs of movement and I left the slab completely unheated the first three winters while I was building.  The local contractors and concrete guys thought I was nuts.  They were convinced that it would heave and crack.  So I'm very happy with the performance of my FPSF - the only cracks in the concrete are the typical hairline cracks that occur during the curing process (should have used more control joints).
"They don't grow trees so close together that you can't ski between them"

small cabin dreamer

Even if I dig all the way to the limestone do I want to pour my slab on that? I dont want a 3-4 foot thick slab? What is the point of your recommendation of digging to the limestone? I was thinking about just leveling the existing soil on top and doing what you did, but you are correct it will NOT perc, it is hard clay over the limestone. I may have to entirely remove the clay and backfill with dirt or something until again level with the rest of the lot and then pour the type of slab you did. That seems almost cost prohibitive. Part of liking this site is that I save money doing stuff myself which I like to do, but foundation work is very tedious to me as my entire home is resting on it. I like the post and pier idea, but do not think it will work on hard clay, and then solid limestone down only about 30 inches.

Jeff922

Sorry, I meant just trench down to the limestone for a frost wall.  But you do raise a good point - what to do with all that clay in the middle.  Your options as I mentioned earlier are:  1)  prevent the high-moisture-content clay from freezing or  2)  make sure the soil/gravel the slab floats on is (and will always be) dry.  It's hard for me to evaluate without seeing it and also, I'm no professional, please take everything as say as only amateur advice and ALWAYS conduct you own research.
"They don't grow trees so close together that you can't ski between them"


Jeff922

I've started clearing for my 22 x 34 barn/shop.  I underestimated how much tree work there is but it's coming along.  I milled this 16' white pine log into slabs (3, 3" and 1, 4") with my chainsaw.  A piece of it will be used as countertop on the passover wall between the kitchen and dining nook.  This tree used to stand where the house is and I wanted part of it to be included in my house. 



"They don't grow trees so close together that you can't ski between them"

OlJarhead

Wow!  How'd you make it through with that little bar?  Looks like it won't pass through all the way??

Adam Roby

Wow, really awesome project.  I just read through from beginning to end for the first time, very inspiring.  So many things done that I never could have imagined possible to do on your own... getting my creative juices flowing.

Thanks for sharing.

Jeff922

Thanks for reading Adam. :D  OJH, you're right, the little 16" bar on my MS290 didn't make it all the way through so I had to go up one side and down the other.  I was surprised how well the cuts lined up.  This work was really asking too much from my little 56cc saw but she got through it...slowly.  I had to file my chain after each pass. 
"They don't grow trees so close together that you can't ski between them"

OlJarhead

I ran a few logs with my Husky 455 but it was really taxed.  I found I could get a few passes with my 10 degree ripping chains and I had a couple of them so I could swap out the chain and mill longer before sharpening both while letting the saw cool down.  I was running a 20" bar though.


Jeff922

I've experimented with ripping chains and I honestly don't notice a big improvement with them.  But I do need a bigger saw and a bigger bar.  Actually, I own an early 1950s Homelite 26LCS which I plan on restoring.  It is huge!  It has a 27" bar and I think it's 103cc.  Now if I can only find the time to get it running LOL, oh yeah, I have to build my shop first. ;D
"They don't grow trees so close together that you can't ski between them"

rick91351

Jeff there are a lot of those old big saws hanging around here in the tool sellers and pawn shops.  My Homelite 410 went bad with a 26 inch bar.  The boot from the air box to the carb was shot.  A friend owns a saw shop he looked it over and pretty well said as much as I use a chain saw it is dead - buy an other.  I bought a new Echo same bar and pitch chain.  I told the shop owner if you can rebuild the Homelite do it.  He said lots of luck but it is still a old saw with a lot of wear and they are not really making parts for them anymore.  About a year later his wife called and told me to come pick it up!   

That was a couple years ago.  It has just sat there under my bench.  Then last week I was thinning pine trees and Echo would not start because a fouled plug toward the end of the day.  I went down to the shop got the old Homelite.  Filled it up with fresh fuel and bar oil.  Choked it gave it a pull and it coughed.  Flipped the choke off and gave it another pull and it roared to life.  Finished out the day with it.  I think it must be twenty years old.  I loved it then and I enjoyed using it again.  However the Echo is lighter in weight and cuts faster with the same chain....  Both are great outfits.

I don't feel I made a mistake having it repaired.....       
Proverbs 24:3-5 Through wisdom is an house builded; an by understanding it is established.  4 And by knowledge shall the chambers be filled with all precious and pleasant riches.  5 A wise man is strong; yea, a man of knowledge increaseth strength.

Jeff922

Cool story Rick!  The one that I have was given to my dad back in the 60s.  It is really in amazing condition considering it's age (I think it was the second chainsaw Homelite made).  The piston isn't frozen and I'm sure a carb rebuild and some tuning and it'll be ready to go.  I'm a firm believer in older being better.   :D
"They don't grow trees so close together that you can't ski between them"

RIjake

Jeff,  I find it interesting that you say the ripping chains don't work so well.  I've been toying with the idea of buying on of those chainsaw mills for one of my saws.  Specifically the Stihl 038 super, I think at 67 ci it should have the power but always thought I'd have to pick up a ripping chain too.
All the pines on my property are about 150' higher than my camp is so it would be tough to use them anyway.  Most of what I have around the camp is beech.  That's pretty hard wood so it would probably be tough sawing.

Jeff922

Getting a bit of a late start (I underestimated the amount of tree work I had to do) but finally started excavation for the barn/shop.  I didn't want to pay $95/hr again for excavation work so I rented one this time.  I've never operated an excavator before (but have operated tractors and forklifts) so there is a bit of a learning curve but I'm picking it up pretty quickly.  I wonder if I should start a separate thread for this build or if I should keep it here as it will accompany my Victoria's?

http://www.youtube.com/watch?v=mpRdcTq2X2g
"They don't grow trees so close together that you can't ski between them"

freezengirl

It has been a long time since I popped in here to see how your project was moving along. Congratulations on the birth of your daughter!  :)