adding on to my home

[countrydreamn]

I need to make our tiny house larger, 913sq me and 7 children full time, DH part time-like one weekend a month.

There is more room out front than in back, there is a well right out my kitchen window and I can't figure out how to build around it, so out the front I go.

I need to know as far as the foundation goes, do I need to put the cinderblock footing under ground or can I just build with it on top?
I know what to do with most everything after that point it's just figuring out this foundation that's got me stumped.

Thanks and I hope that this is the right place to ask this.

Oh and if it matters I live in the middle nowhere AL, I do not belive that I need any permits or that there is any building code or inspectors. I will of course be double checking this before doing anything.

[ronbre]

first, is your home a one story..if it is..the best way might be to build up..no foundation to worry about and your money savings could be huge..esp if the roof is in need of replacement soon anyway..

you are not in a frost region so you shouldn't have to go really deep with your footings..but i would go at least 2 feet..just dig a ditch around where you are going to build and pour on some quickrete from the home improvement store and level it well..use a good level..and some good trowels..they are both cheap..then you can lay your blocks right on that..and morter them in well and make sure they are level..use a string and a rubber hammer to tap them level..when you put in your morter ..pick up a roll of banding tape with holes in it..and put it in the morter every several feet while wet..(you'll need a snipper to cut this)..you can then use this to screw up over and on top of your sill board..and then it will hold it securely to your foundation..thus..help against high winds.

build your walls up on top of that and use a lot of bolts and screws to fasten things well.

ive done a lot of building ..mostly on my own..roofs are hard though..so you'll need some help there..easier for two people than one..or even more..

measure twice ..cut once.

do consider building UP rather than out though..

[Callieslamb]

When you check with the building codes for your area, they can tell you how deep your foundation needs to be. I wouldn't build without a foundation. It won't be very deep. In W TN, it was 24".

Since you are in tornado alley - I would bolt the cinderblocks to the foundation.

[TnAndy]

The cheapest and easiest type of foundation is a post/pier type....often used on older houses in the south where colder weather isn't as much of an issue.

You dig a hole couple feet deep, pour a pad of concrete 8" thick and 16-24" in diameter, then set a short post of treated 6x6 on the pad and run your flooring system on the posts...very similar to how a deck is built. Even better is to pour a concrete pier on top the pad in the ground ( sink some re-bar in the pad when you pour it to anchor the pier to the pad. You can buy round cardboard forms, called "SonoTube" at the building supply stores for this....you simply cut the tube with a knife or saw to the length you need to get all the tops the same height ( level of course with each other ), and pour the tube full of concrete mix, sinking an anchor bolt in the top. When the concrete has dried, the Sonotube 'peels' off very easily, leaving a nice, round pier for your wood to sit on.



If you don't want an exposed under floor, you need to do a crawl space foundation. This requires a continuous concrete footer 8" thick, twice the width of the block you intend to lay on it ( usually 16" minimum ). The bare minimum for the number of courses of block is 3 high, giving you a 24" high space under the floor to access for work later, like insulation, water, electric wiring. The footer can be hand dug if it's not too big....you need to be 16 to 24" deep to the BOTTOM of the ditch in your area so frost doesn't cause the ground to heave and crack your foundation later. The position of your footer will depend on the height of your current floor, IF you want the floor of the new addition to match the existing house. You need to measure downward from the bottom of the existing floor joist sill plate at least 24" ( for 3 courses of block ) and then in even 8" increments from there....so the top of your footer would be 24" or 32" or 40" (and so on ) down from the bottom of your existing wood sill plate now.

Here is a pic of a small crawl space foundation with a hand dug footer for a chicken house I built last year. I only went 2 blocks high, but I also never plan to get back under it, I only did this type foundation to keep critters from living under the chicken house. Note the 4 places left out for metal foundation vents, which you need to allow the space to vent ground moisture. You can also see the wood sill plate bolted in place, ready to build on.

[gladetop]

TnAndy, I have been doing a little research lately, and the new thought on foundations for the southeast u.s. is to not ventilate. The new way is to seal the crawl space off with a vapor barrier and to insulate the ends of the floor joist that rest on the silplate.
Its interesting to read thier reasonings and the conclusions they have come up with.
Don't know if I would do it that way yet. But is something to think about anyways.

[ronron]

This reminded me of something my brother did that is kinda off the subject. a few years ago he was driving down the road and saw one of those rooms that people tend to add on to single wide mobile homes.....He got to looking at it and realized it was really well built......the mobile home was long gone....he asked the property owner if he was going to do ahnything with it and he said shove it over.....so my brother asked if he could have it the guy said yes.....my brother took it home cleaned it up put down new flooring paint etc. and attached it to the back of his house for a storage entry computer room...keep in mind that my brother is very well off with a huge cedar home this thing ended up looking pretty nice...you would never know where it came from...I have always thought this would be a good business building modular rooms for people who need an addition.....I have always looked at these things differently since then.

[Joshie]

You can't just pour a slab. You need to put footings under a slab.

[haypoint]

You can't go too far wrong if you copy the foundation method of the existing home. If you had a floating slab, concrete poured on top of the ground, I'd add on the same way. If you have wood or concrete pillars supporting the floor joists, continue the same under your addition.
What ever conditions, like moisture or frost, affect your house, the addition will be able to react the same way.

[Mel-]

here is a page I have book marked on post and pier foundations you can do yourself:

http://www.countryplans.com/foundation/index.html

I know they work well because my grandmothers house in tennessee has been on the old fashioned kind (boulders) for almost a hundred years and my house and my parents house on the same farm have been on boulders for close to 150 years.

[Jolly]

A lot of stuff is local.

Down where I live, there is a lot of clay. You sink conrete piers with a slab in that stuff and the expansion and retraction of the clay will snap your foundation. Much better to pour a semi-floating slab...your footings are only about a shovel wide and about a shovel deep, and that's on the perimeter.

And speaking of houses on piers...most of the old homes down here are built on piers that rest directly on graded ground..seems to have worked for the last couple of hundred years or so...

Again, what works best is local.

[TnAndy]

Originally Posted by gladetop

TnAndy, I have been doing a little research lately, and the new thought on foundations for the southeast u.s. is to not ventilate. The new way is to seal the crawl space off with a vapor barrier and to insulate the ends of the floor joist that rest on the silplate.
Its interesting to read thier reasonings and the conclusions they have come up with.
Don't know if I would do it that way yet. But is something to think about anyways.

Don't know that I'd buy that without a lot of years in that research...and the vapor barrier would have to almost perfect.

Neighbor of mine built a rental house on a crawl space, and had the floor joists literally rot out from under it. He thought he had simply bought bad lumber until he brought a piece of it up and I checked it with a moisture meter....well up in the high 20% range. Then we both went down and looked at his foundation....almost NO venting (did have a plastic vapor barrier on the ground ), but one long side of the house let rain water run against the foundation, so not only was there no vent on that side, but the additional water kept the crawl space very damp. He replace the joists ( a MAJOR PITA ), added more vents, re-graded the slope on the uphill side, and also added a power fan on a timer. Problem seems to be solved ( 10 years now ).

[countrydreamn]

Thanks for all the replies.

This house was built in 1939 and there are stacks of bricks on all the corners for the foundation, then at some point some went around and put up "cinder blocks" to make it look like a real closed cinder block foundation.

So today what I found is that for two sides at 14 ft and then the front at 37 ft, at 3 ft high I'd need 195-200 8x8x16 blocks, plus the guy quoted me for 8 bags of premix, but then said I probably should get 10 for 339.81 plus 25.00 for delivery.
I have a guy coming out first thing tomorrow to see and let me know what it's gonna run for the poured foundation.

Now there are a few other building supply places I can check that are local as far as I can get delivered and not run too much. I could also go to Lowe's and see what it would all cost there and get 10% off the whole purchase because DH is military, but I don't know what the delievery would run as I am a bit over an hour away. I might call and see tonight yet what that would cost.

The older boys and I still need to get out there and start digging and get this project rolling before it gets too hot, but it's still going to be a very slow going thing as it'll be me and my boys.

So if you guys have any ideas on how to make this any eaiser please share them. Cause I know it's going to be a lot of hard work and we are doing this as I've got the money to keep going. But praying it'll be done by the end of the year.