Porch construction questions

[Egon]

Re: Porch construction/massive footers OK?

ejb:

Sounds like you got a viable plan all worked out. There are saddles to place rebar on but with the mass you have it won't matter.
Egon

 

[patrickg]

Re: Porch construction/massive footers OK?

("I figure for the bottom rebar I'll put it in 8 inches up from the bottom, resting on some
stones..any problem with that plan?")

Consider the reasons for the rebar. Concrete has great compressive strength but little tensile strength. If you made a concrete beam to be supported at each end and carry a load in the center, where would you want the rebar? You would want it near the bottom of the beam to keep the concrete from puling apart at the bottom since the bottom of the beam is in tension while the top is in compression. If the beam were ballanced on a pillar and carried weight on its ends then the rebar goes near the top. If the beam were to be subjected to loads that could go either way then you need rebar top and bottom. Why not the middle as a happy compromise? The center of the beam would esentially be neutral, neither in tension or compression and the rebar wouldn't help add strength.

Rebar can also serve to keep cracks from allowing pieces of concrete to migrate out of close contact with the "mother" chunk. That is, concrete virtually always cracks but rreinforcement will hold it together and can make cracks remain small cosmetic blemishes.

So, decide what the rebar is supposed to do and place it accordingly. It is likely that 8 inches up from the bottom in a 3 ft thick "beam" is OK but why would you want it higher up than say, 4 inches? What forces are at play on the concrete in question? Are they trying to make it bend concave up (would hold water) or concave down (would spill water) or what?

(" I also planned on putting about4-6 inches of gravel at the bottom of each hole first
before the pour.")

Won't hurt and could help with drainage if the soil will permit. If mud (concrete mix)is too soupy it will negate the effect of the gravel by filling it up and making it a weak piece of cement.

(" Using earth-forms (i.e. the holes themselves as the form) how important is it that the
hole has nice straight edges etc?")
Just aesthetics as long as you don't make any "stress risers" to help the crete crack.

(" Also, should I decide to build some of the forms out of wood, someone mentioned that it
would be necessary to remove the forms when I am done....is this really necessary? I
was just going to let them rot in place??")

Can you say termite? Why chum for termites? It is good practice to remove all forms, grade stakes, and wood debris.


(" Oh, I was planning onusing 3000psi concrete? Sufficient? ")

Maybe, probably... with enough rebar properly placed, IF the stuff they deliver arrives and gets placed, retaining 3000psi character.

There are a couple other imposible questions you forgot to ask. How high is up and how long is a roll of string.

The good news is you are doing pretty good. The bad news is that it could take years before you would know that you didn't quite do good enough. The difference in the cost of those two options can be staggering.

Patrick (Please lurking keepers of all that is good and holy, no email flames regarding depriving termites of wood scraps)

 

[patrickg]

Re: Porch construction/massive footers OK?

Now Egon, You are taking me out of context. Clearly my 25% comment is for a house with most construction tasks done by subcontractors managed by a general. In that scenario, getting out there with a hammer and saw is a poor second place to the contribution/savings available to you through being the general contractor.

Now, as you were the general contractor in your example, I guess that is another slant on this. You are agreeing with me that being your own general can save 25%. You did it and saved a lot more. Thanks for the confirmation.

How did you do in the average hourly wage category while wearing subcontractor hats? I find that I am always slower than the real pros so I have to work real cheap. Anyway back to the topic. I bet you made much better wages for your general role than you ever did as a sub. That said, if you wanted to speed up the process by adding someone else's labor, the best addition would have been a sub or helper, not to replace yourself as general, wouldn't you agree?

Patrick (Please no flaming emailsfrom the lurking guardians of of the public good regarding Canadian-American relations as Egon and I have NO problem.)

 

[ejb]

Re: Porch construction/massive footers OK?

Thanks for the very detailed response...in my area, termites are almost none-existent, and getting the forms out, should I choose to use them, would be difficult because my plan was to build them and then backfill around them to hold them in place and counteract the weight of the concrete...so it would be necessary to re-dig the holes after pouring, which seems like a lot of extra work to me (but I agree, if termites were a problem they should be removed)...maybe I just use earth forms and avoid the problem altogether....

I guess I'll lower the rebar a bit..say4-6 inches from the bottom, and proceed from here...as you say, it will be 10-20 years b4 i really know if I screwed up....

 

[braveheart]

I have built many porches and everything sounds peachy so far. Just a little tip for you that may save you some time in roof construction. Most sunroom company's use a light weight but very strong roof system made from 3" - 6" styrofoam panel that are aluminum clad. The thicker roof panels also have a 1/2" plywood panel underneath the aluminum to fasten stuff to. It will save a lot of time in constructing and is much lighter in weight. Some roof panels are very decorative.....good luck....sounds like your having fun....these panels are roughly 4' x whatever you need and you can put skylights in too also will easily span the distance required....

 

[Egon]

Re: Porch construction/massive footers OK?

Patrick:
Being a bottom feeder my wages were always lower than that of a certified tradesman. Doesn't mean I can't do the job as fast as a tradesman. Pulling wire and glueing pipes goes pretty easy. Cutting wood aint that hard as long as you got a board stettcher handy. Probably seen more concrete than most tradesmen. Putting in the septic is pretty simple if'n you remember the honey runs downhill and a quarter of a bubble is minimum slope.
Now for the economic side, as the one Lad stated, you have to figure in taxes and then also put in a factor for loan interest and it's surprising as to the results.
Egon

 

[Egon]

Re: Porch construction/massive footers OK?

Patrick:

Shall we pre or post tension the rebar? We'd also best determine the rebar spacing and size based on the maximum size of agregate and concrete strength. Then we could also pour no slump so there would not be a problem with the soupy bottom.
Egon

 

[patrickg]

braveheart, I toolike that aluminum & foam panel roof. had a 14x22 foot porch with a 2 inch thick foam clad in aluminum roof. The panels went together with camlocks really easily and in 14 years, never a leak until we walked on the "walkable" roof. Then some good caulk on top along the leaking seam fixed it fine. Excellent insulation value and an attractive enameled pebble finish that looked fine on the inside. It took the intermittent steam of a jacuzzi all that time with no evidence of corrosion at all so should take regular weather real well.

Patrick

 

[patrickg]

Re: Porch construction/massive footers OK?

Egon, Since I am a graduate magnum *** nauseum of the Christopher Columbus School of Touch Typing where we look for, discover, and then land on the keys one at a time, I can't keep up with your rapid pace of volleys of posts,
G A S P...

Anyway, my congratulations on building your own house, please share some pix! I can do many of the jobs required, especially wiring, plumbing, septic design and install, flatwork and masonry walls, stucco, painting, plastering and so forth but to stay within code, on applicable tasks, I like to have someone current in it to be involved. I can do a passable job with architecture and design and also with the civil and mech eng and even saw and hammer although I have broken a finger by hitting it with the hammer and I am of the "I cut it off three times and it is still too short" school of carpentry. My greatest lacking is in practical experience working with knowledgeable people. The figure it out from scratch approach is not economical or practical sometimes. Everytime I work with a pro I learn a lot. Easy since much of what I see is new.

I will be using ICF construction for at least the master suite walls, interior and exterior and for the guest room in the walkout basement. Costs permitting I will use them for all the rest of the exterior and load bearing walls as well. If I have a second floor it will be reduced in size to fit within the space captured by the high pitch roof and will only add the cost of sheathing, insulation, siding, windows, etc where there are dormers and such. This is for economy as well as "THE LOOK" we want. I have never done ICF walls before and I don't want to be the guinnea pig for my first attempt. Similarly, with supervision I have done roofing but don't want to be responsible for directing the job. This is the way of a lot of the labor of construction. I can do it with supervision but don't wan't to trust to brute force and awkwardness and do it myself unsupervised. I envy all the folks who can literally build their own house from the ground up. I am sure I could do it but I am also sure I would not be happy with the mistakes I would make which would force me to accept something I don't like or tear it out and do it again (which I like even less).

My hat is off to anyone who is willing to ask some questions and give a construction or remodel job a try. The "can do" attitude is real important as long as it is tempered with a little common sense. What scares me is knowing that folks (myself included) are the most dangerous when they don't know that they don't know.

I hear you on the topic of the cost of money, basically a net present value sort of calc. Luckily I will not be getting a loan as this house will be built on the proceeds of the sale of my previous house. That makes it serious buisness to not have an overrun since my income stream hardly warrants the name. I can aford to do it once and do it right the first time. I can't aford any high dollar messups. I suppose that motivates my conservative approach and reliance on professional help. If I were knocking down a good salary I could aford more risk but oh well...

Patrick

 

[crb478]

You can use ground forms for the base and still form up the top area with wood or wood and sono tubes properly braced. Just coner the edges of the wood with a little dirt. I personally would remove the wood since it will rot and settle later even if termites are not a problem. It is a code violation around here to set rebar on rocks, compression strength of the rocks is unknown so it could weaken the footing. You can drive rebar into the ground vertically and then wire the Horizonal runs to that, or buy what is refered to as jacks that hold the rebar at a set height. Jacks resemble the toys but are made from plastic and can be set at different heights depending on which way they are turned.