We are first time homeowners, and I want to put an addition on our new house. The house is a ranch style, and is essentially a rectangle, with the exception of a small 19′ x 7′ area which serves as a porch. We want to bump the house out so it is a true rectangle. The house has a crawlspace, beneath it, with a low foundation wall.
Here is the question. I want to do most of the work myself. I am handy, and have done framing, roofing, furniture, etc… although most of it was years ago. Can a newbie like me do the foundation work myself? It would be an “L” shape, 19’x 7′ that would tie into the corner of the house. My girlfriend thinks I’m crazy. Am I ? I think I could excavate, make the forms, add the rebar, and hire someone to pour it.
Also, does anyone have a guess as to what DIY would cost vs. hiring a contractor?
I am in Northern Ca
thanks !
Edited 10/8/2005 2:13 am ET by cykeler
Replies
Welcome to BT. Hold on for a possibly bumpy ride!
I think my footer guy charges around $3 a linear foot to dig and pour - materials (concreta and steel if necessary) are extra. Take into account though that we don't use forms here in this part the SE US since the soil is heavy enough (non granular) to act as a form.
I think that yours is a bad idea, and particurally since you want to dig and have someone else pour. I think you will have a distinct possibility of doing the digging and then having the open excavation sit for several days to a week or more while the concrete guy gets around to showing up, all the while, your footers possibly being filled up with rain water. Further, the equipment rental for the machine and a laser level will be nearly as much as a pro will charge to do a turn key job.
Hire out the footers and foundation and then DIY the rest if that is what you want to do.
Edited 10/8/2005 6:14 am ET by Matt
you are not going to save any money, but yes you can do it, I did mine.
I had zero concrete experience when I started our all-concrete house. Read everything I could get my hands on first. Didn't have BT for advice.
Hiring somebody to do the pour sounds like a bad idea to me. Seems to me you should either do it all or get somebody else to. If you decide to do it, the how-to form book I used was " Construction Manual: CONCRETE & FORMWORK" ISBN 0-910460-03-5. The American Concrete Institute and the Portland Cement Association both have inexpensive booklets on the subject.
Watch out though. After building our place I got to be known as a concrete guy who could do just about anything with it. Changed my professional direction a bit.
If time is of the essence, hire it out. I only did mine after I was unsuccessful in finding somebody to do it.
PAHS Designer/Builder- Bury it!
GO FOR IT!!!
Why have somebody else pour even?
Now is the time when young and energetic (however,what does your"Years ago"phrase mean?). Wife and I did 100% of our house when in 20s.
Others will dispute it, but by scounging, surplus, and other techniques you can quality build your addition for less than $20 sq ft total DIY.
Go to library and look at finehomebuilding 'great moments', Nov 1990, for how to build a cabin for under $1 a sq ft.
If you can handle the excavation yourself (handy with a mini-ex are you?)the footing form and pour should be no problem. Use forms so you have something to level and screed off of. The rebar in your footings need to be correctly sized and ideally should sit about 1/3 of the way up from the bottom of the footing. Hammer drill holes into your existing footings and epoxy in some rebar stubs to join the the old and the new. Set in vertical rebar before the footings set up.As far as the foundation walls go, if it's going to be a conditioned crawl space, I would use ICFs. Although more expensive, they are very intuitive to put together, and the pre-pour bracing is straightforward. Since this is a one time shot, building forms can leave you with a bunch of off sized lumber that you may not have a use for. Don't forget your anchor bolts!Yes, you will save money depending on you personal accouting methods. If you spent the same amount of time that you will spend on this working at your "normal" job, and use that money to pay someone, it will likely be a wash. But if you already spend as much time as you can stand at your 9-5, and this will be a night and weekend project, you obviously will come out ahead.P.S. This recommendation assumes you are at the upper end of what the term "handy" is typically understood to mean.
I have a situation virtually identical to the original post. 8' x 16' that was the old back porch of a 30' x 50' Queen Anne. I want to do the same thing he is talking about but here's the wrinkle - my foundation is brick and has a full basement except for this section under the porch. The foundation walls come up out of the ground 3' leaving the basement actually 4' deep.
I want to have it done by someone but haven't found anyone yet (small rural town) because it's not a big enough job. I'm considering doing it myself but my concern is tying it into the brick foundation. The footers on the brick foundation are bricks that are placed at an angle from the wall. What is the best way to connect the footers and the walls?
I'm with junkhound.
You need to pour the footing first however, and then the foundation wall.
The house has a crawlspace, beneath it, with a low foundation wall
Does that mean a poured wall, or a CMU wall?
Pouring a trench footing is pretty staight forward, and can be done without a laser level. I do it all the time with a transit or builders level. You just have to be carefull to set the grade pins, no matter what insturment you use.
Buy some books as suggested and go for it.
Come back here with more questions, and then sort through the answers for the ones that fit your situation.
BTW, welcome to Breaktime.
Dave
Things to consider:
Everything has to be square, plumb and level or it will haunt you through every single step in your addition after the foundation. If you don't have the ability to accuratley layout, hire a pro.
Wet concrete weighs something like 150 lbs per square foot. Your form has to be built to hold the weight or it will shift or blow out and you have the first problem.
You will have to work closely with your building inspection department. If you are in an area like I live in that doesn't have one, then talk to a genuine expert about what is needed in your area as far as type of foundation and details.
The addition has to be compatable with the existing house or you could have some movement which causes cracks etc.
I am a remodeler in a rural area and there are alot of very self sufficient who have done their own work and didn't have to do anything to a code. I end up working on the house sometime later and have some real headaches.
Foundations are the most expensive and troublesome things to correct if they are not done right. It is not rocket science, but does involve some skills to end up with a good job and is alot of hard work. Depending on your schedule and motivation, it might be more enjoyable to have a pro do your foundation and focus on the addition.
Edited 10/8/2005 10:37 am ET by fudude
Basic foundations are like driving--it takes a while to get the feel of it, but just about anyone can drive around the block with no experience if they are cautious and go slow. Those with no experience who think they can go fast end up in bad situations. You're on the right path by stopping here, but be careful since taking bits and pieces of information from differing sources and putting them together can either work great if you have a nack for doing things right, or it can work terribly wrong if at the opposite end. I'll pass on what major problems we've seen with DIY foundations.
The worst thing that can happen is you'll finish pouring your walls and something critical will have been left out and a building official will say you'll have to tear it out and start over. If you are in a jurisdiction that requires building permits it can be expensive to skirt the system, especially if it's not built right, although many people do. Once upon a time I worked in a county that would pull the home's electric meter after 30 days of noncompliance with the building codes and some homes sat vacant if the home owner didn't have the resources to tear out and build correctly.
A close second would be having your wall forms give out. It's not hard to form well, it's just easy to underestimate how heavy concrete is. Just be sure and remove mud the same day if that does happen.
Then there are the uneven/unlevel/ugly wavy walls. If you are completing what is essentially a rectangle, use string lines to keep your new foundation in line with the old. Check forms with a string before the pour, string after the pour, string your sill plates, etc.
Concrete will leave voids on the surface if it's not vibrated or tamped through with a piece of rebar. I've seen some voids large enough to put an arm through. Everything can be fixed, but it's much quicker to simply vibrate the mud.
Fully think through the lengths of your sill plates and make sure there are j-bolts in the proper locations. This is a common mistake that young carpenters make and is very easy to prevent.
In the old days before transits and laser levels, a simple water level (clear tube with water in it) worked and it still works today, albeit slowly and sometimes painfully. I'm one of the few carpenters that still uses a type of water level regularly and the guys on the crew check/calibrate their lasers against it.
It's a great idea to save the money on the foundation by doing it yourself. Your significant other will think you're taller, smarter, and more handsome after she sees how much you've saved.
If it were me I'd gather as much information as possible before starting and check on local building code requirements. Also, hire an experienced carpenter to go over what you're doing before building your forms, to check your forms prior to pouring the walls, and to help direct/finish the pour. The time will probably only cost $100-$200 and will head off many common mistakes.
Best of luck and let us know how it turns out.
Don
Every thing has got to be Level, plumb, and well braced!
They do allow a little (correct me if I'm wrong) variance in the footer, but make it perfectly level and you will have less headache building the stem walls.
I think you can do it, just read up and take your time to do everything right!
One more thing that has not been mentioned. Concrete is very caustic. First time I poured over 20 yards in a day barehanded the tips of my fingers were scabs the next day, same thing with knees (even on foam pads) after finishing a 145 yard floor without waterproof kneepads. Waterproof kneepads and waterproof gloves.
Definetly rent a vibrator as said before. Watch the form ends and corners when vibrating unless well tied forms, any tiny movement and you better brace it up quick.
You got a point there buddy.
Concrete rash sucks! Every bag of portland should come with a little dove moisterizer............When in doubt, get a bigger hammer!
Do you have access to past issues of Fine Homebuilding? A few issues ago, an author/builder showed how to form and pour a foundation for a small addition using plastic foam insulated concrete forms (ICFs).
My local building supply yards have all taken on one brand or another of these product systems. Typical brand names are Polysteel, Logix, Arxx, and more.
Here, the lumberyard that sells you the lego blocks, also lends you the engineered bracing components, but you have to supply your own planks.
It is not cheap, but it is a way that a builder can build his own foundation (or entire house), without needing to buy the services of a concrete foundation contractor.
To compare it apples to apples, you need to factor in all the things you get with an ICF foundation that you don't get with just plain reinforced concrete. Depending on the product, there is quite an insulation factor to the walls, due to the foam. Both inside and out, you have a surface you can readily attach things to, like drywall on the inside, and diamond lath, board strapping, siding, etc. on the outside.
A builder doing a job across the road from my project spent a week with a Logix package, after he poured his footings, assembling everything and getting ready for the pumper truck and ready mix loads. In five hours of pour time, he had himself a complete house-and-garage-and-breezeway foundation, complete with window openings on the downslope side. He had never done it before, and had minimal help.
As a DIYer who did what you're about to do only WORSE (full basement, underpinning of existing foundation wall, heavy clay soil etc), and with no more prior concrete exposure than it sounds like you've got, here's my two cents:
- unless you've got experience with the machinery, hire out the digging. Get competitive quotes and BE THERE during the whole dig. My bobcat guy cost me less than the rental alone on a bobcat would have cost me because he drove the thing like a freakin' madman AND he kept the roll-off boxes for soil disposal coming in a steady measured stream- no waiting. Experienced people do this stuff both accurately and FAST, which saves money. If you're just digging strip trenches for a crawlspace foundation, the advantage of hiring somebody might go away somewhat, but it may still be cheaper to hire it out. Get the RFQs out and figure out how many hours of machine rental you can get for that- unless you're confident that you can save yourself the guy's bill-out rate for his labour, don't bother doing it yourself because you'll do it SLOWER than he would by a long shot and hence you'll incurr more rental costs.
- KNOW your soil conditions. Don't start work without knowing the soils type, the depth of the permanent water table, and what sorts of foundations work in these soils. If you have tough soils, hire out the foundation work and supervise the heck out of it. And in California maybe moreso than just about anywhere, make sure you get permits- those folks know something about what it takes to survive an earthquake and won't let you build something totally inadequate. I'm not stating the obvious- i.e. don't undermine your foundation or that of your neighbours etc. Okay, I stated the obvious, because sometimes it ain't so obvious!
- first step, before you even draw up your plans: measure your existing foundation using ACCURATE TOOLS. Don't trust laser levels unless they're top notch and they've been recently calibrated- use a water level. They're a PITA but they're tough to fool yourself with. It's nice to build an addition that's level, but not so much fun if the existing house already slopes a couple inches from level along the wall you're building to. If that's the case, go into it with a design strategy to deal with the problems associated with this sloping BEFORE you set your forms! In my case, the wonky area was hidden behind a garage which made it impossible to check the whole length until the demo was done.
- brace your footing forms across the top- don't rely on stakes, regardless how many and regardless how well you've driven them into the soil. Don't worry that you won't be able to screed properly under the ties- it's far more important that your forms stay where you put them throughout the pour. Man, I wish somebody had told me that! We had a form let go, and fortunately it was just a mess and a lot of work to fix it. Unfortunately I wasn't wearing waterproof gloves, so I lost two nights of sleep and a weeks' productive work because I burnt the sh*t out of my hands in the panic to deal with the form failure.
- you're a DIYer, and hence you have no forms for the stem walls. Unless you can find a use for the form boards as sheathing etc. AND you're a glutton for punishment, USE ICFs. They're intuitive to use, work extremely well when used properly, unlike homemade forms they are VERY UNLIKELY TO BLOW OUT UNLESS VIBRATED EXCESSIVELY, and in my area they cost LESS than the plywood and lumber to build single-use forms. In fact they cost only modestly more than what the foam to MAKE these forms would cost at my local Home Despot. Do a search here and glean the wisdom of many who have gone the ICF route before you.
- don't be afraid. Arm yourself with knowledge. Where you're concerned, hire a consultant for help- money well spent if you find the right person, and still cheaper than hiring somebody to do it all including the grunt work.
I saved a sh*tload of money doing my own foundation work. I got a top-notch ICF reinforced concrete foundation for both my addition and my garage for less than a "pro" would have charged for a concrete block POS for the house alone. And I lost 20 pounds digging the underpinning trenches! Best of all, I have the beautiful sleep-at-night factor that comes from being the one who did the work and knows that it was done right and no corners were cut while I was off at my day job.
Best of luck to you.
Hard for me to believe that ICFs would be cost effective for a crawl space - even DIY... I can have block installed for about $4 a square foot of wall - maybe less - turnkey. How much are the ICFs, concrete, etc?
You're getting much better pricing than I was offered. MUCH better. Based on actual quotations, not unit rates. Depends on your access to good subs I guess. Right now my region is booming and everybody's stacked with work, so the likelihood that a homeowner GC gets ripped off by an incompetent or crooked sub is pretty good. At your unit rate I'd agree- it's a no brainer: hire it out because there's little to be saved for too much labour and risk. CMUs are plenty good enough for a crawlspace. But I'd have a firm quote in hand before I made the decision.
Around here you'd need to fill the cavities of the CMUs so there's still a fair bit of concrete involved in either approach. You are also required to parge the exterior of the CMU wall when done. The footings are the same for both.
The ICF forms themselves are cheap- I paid ~$18 Canadian each for a 4'x16" high form, which is 5.3 square feet of wall, and I'm sure that contractors are buying them at a better price than that. That's less than the cost of 3/4" ply and lumber to make a single use form of the same wall area, which was my point. Stacking the ICFs is an easy job, especially if the walls aren't tall. There's some rebar in there too which adds to the cost.
Would ICF make a good waterproof basement?
Absolutely.
Like anything, you have to detail it correctly; usually a peel n stick membrane or dimple sheet, drain tile and gravel etc, but the basement should be warm, dry and ready for finishing.
Treat every person you meet like you will know them the rest of your life - you just might!
Keeping your basement dry has more to do with providing adequate drainage than it does with "waterproofing" per se. Our soils mean you either have a sump pump with properly detailed footing drainage or you will have a wet basement eventually.
My ICF foundation is as dry as a bone and it's in heavy clay till. Any water coming anywhere near the house ends up in the backfill against the foundation because it's probably 10,000 times as permeable as the native soil. You either pump that out at the footings or the house will be swimming in it. Regardless how much tar or membrane you put on there, water will find a way eventually.
FYI, my ICFs have that rubberized latex Blue Skin coating under Platon dimplesheet membrane. The dimplesheet acts as both a physical barrier to water plus a "french drain". The air gap between the dimples and the exterior foam ensures that any water which makes it through the Platon can flow freely to the footing drainage layer, which the pump keeps dry so there's no opportunity for water to pond against the wall and find a crack to seep in through.
>> Around here you'd need to fill the cavities of the CMUs so there's still a fair bit of concrete involved in either approach. << We don't fill the blocks unless there is a significant amount of unbalanced fill, (outside VS inside the wall) which would pretrain to a basement, but not normally a crawl space. The OP said he had a low crawlspace - or something similar. I suspect you may not see to many crawl spaces in Canada - depending on where you live... If you gotta dig 4' deep footers, you might as well dig a basement.
>> You are also required to parge the exterior of the CMU wall when done. << Right, but I was assuming that this would be necessary for ICFs also.
>> The ICF forms themselves are cheap- I paid ~$18 Canadian each for a 4'x16" high form, which is 5.3 square feet of wall << Looking up the exchange rate that is ~$15.30 US or about $2.88 a sq foot. I don't know what kind of block you are using, but let's say that it is filled with 6" of concrete @ $85 US a yard. That's ~3.14 a cu ft, or for a 1/2' thick wall is $1.57. So adding the 2.88 a sq ft for the ICF and 1.57 for the concrete = about 4.45 a sq foot of wall for materials only. I didn't add for rebar assuming that on a "low crawlspace" it wouldn't be needed. So, my estimates are ~$4.45 US a foot for ICFs materials only vs ~$3.75 US a sq ft for CMU block - complete.
>> Right now my region is booming and everybody's stacked with work, so the likelihood that a homeowner GC gets ripped off by an incompetent or crooked sub is pretty good << Construction is booming here too... Wonder if this gas thing is gonna put a damper on that... Back to your statement though, yea, well similar rocks get thrown here a lot. The fact is that if one knows how to handle a jobsite and are willing to pay what other people's time is worth, you can find good subcontractors. I know, it's hard to feel comfortable paying someone several hundred hours an hour, but when (in this example) he shows up with 4 bricklayers, 4 helpers and 4 laborers things all of a sudden happen fast... and with a GC who knows what to look for everything comes out good. On the other hand a GC who tries to manage the job from his office has problems...
I'm sure you did save a lot of money DIYing your basement - assuming that your time is not worth anything... And I'm sure it came out good. I'm just not sure using ICFs is the way to go for a low crawl space.
I'll add my two cents: Foundation of a house is very important--I know because the old house I live in has a bad foundation. If you don't do it right and things start to move, settle, leak, etc., then everything you did from the foundation up is ruined. I do many things myself, but I'd try to hire it done if I could afford it.
I'm crazy. Am I ? I think I could excavate, make the forms, add the rebar, and hire someone to pour it.
Also, does anyone have a guess as to what DIY would cost vs. hiring a contractor?
That all depends <g>.
First off, what sort of foundation are you thinking of? You've gotten a lot of often hard-learned advice on stem-walled foundations, mostly debating poured wall versus block wall versus ICF wall. The advise is good--but not if you were planning a slab-on-grade.
You're in Northern California [insert plea for updated Profile info], that often means you need an engineer for a seismic-rated foundation (whether you want one or not). Is that the case?
Once "we" know what fondation system to match, to use, or is specified by the architect and/or engineer, "we" will be much better placed to answer your question.
If you are getting a stemwall crawlspace foundation, the depth of the new floor has to be matched to the existing floor where the two meet rather precisely. This can add wrinkles (read, complexity) to the foundation design. (Might be simpler to use a 10" TJI to span the addition's new floor, than to match the dimensional lomber used orginally, for instance.)
And, since you are in North Cali, the issue of waterproofing is medium-critical, too. The foundation will need to be detailed for drains and the like (and, possibly, matched to any existing drainwork).
So, can you do it? Sure, it's entirely possible you can. First we have to know all that you'll have to do. (Like getting rebar inspected in a pre-pour inspection to AHJ-required rules.) The labor part can be the easy part--the leadership part can take more effort than it might seem up front.
Cheaper? That's a whole 'nuther question (thread). Me, I can specify a complete foundation system that will pass full muster in my town. I even know where (ans who<g>) to take all the permit forms to. I can bend and wire bar to spec. I can hammer formwork together (even know the person to get forms from at Sheppler's, if that's needed).
Except, I know two different concrete guys who can get the job from open hole to finished concrete far faster than I could (especially as they have a much larger, more experienced, finishing crew for slab-on-grade work).
So, in my case, for foundation work, my not-for-profit supervisory hours are more valuable than my not-for-profit labor hours. That's what would steer my choice. Your case might be different.
No. California is a big area. Annual rainfall can range from 80+" to 15" or less, and of course that all comes in 4 or 5 months (we don't even know how to think about protecting open trenches or roofs most of the year). Soil conditions fary widely as well from sandy to clay masquerading as concrete. So the drainage issue is totally site-specific. Definately needs to be addressed, prefferably by someone qualified.
If you're not in the mountains you typically won't need anything more than 18" below grade - with only 26' of foundation you can even hand dig. All depends on your time vs. money equation. The GF will probably like the results of the hand-digging ;-). Also, ICF doesn't make any sense - just form it up.
Depending on your local building dept. you may be able to get by with designing the foundation (footer width & depth, rebar schedule, how you tie back to the existing foundation, sill plate tie downs, etc.) or you may need to engage an engineer for the design. If it is as simple as you make it out to be the engineering might not be too expensive. It WILL be overengineered due to stupid CA liability laws, but that's part of the price of living here.
Given the size of the project and the current state of construction around here you will be lucky to find even a total hack to do the job in your lifetime. So - go for it! Oh yea, and what everyone else said about level, square, braced...
Go for it.
It ain't rocket science, get a couple of Taunton's books and figure out what needs doing.
Ck with the building department, buy the code book too. Is CA IBC now? About $80 I think. You'll need it by the time you're done, might as well spend the money now. It's a tool, just like the rest.
Someone mentioned a water level in an earlier post. That's the cheapest & most accurate tool you can find for this particular project. You'll need to do the research to find out who & what a water level is, but it's worth the effort.
The chances of finding anyone competent to take on a small job like this is approximately zero around my area, even a return phone call would be a minor miracle.
Research, a couple of friends for the pour & thorough planning is the answer. When that concrete starts down the chute, you've got about 20 seconds to figure it out.
Good luck, Joe H