In this thread: I post stupid questions and images of building plans.

[Building]

One of the things I like most about this forum (longtime lurker) is that there's a real do-er spirit.
On some other forums relating to building, etc, basically every answer resolves back to "HIRE THE PROS" and a mocking tone towards anyone who dare think they can do anything themselves.

I'm building a small place.
I want that place to be 32' long by 24' wide. It will be in Florida.

I am drawing my own plans with Layout and trying to interpret the Florida building code as best I can.
For this first post, here's an image of my foundation.



It will be a 16" wide trenchformed concrete footer with 12" sonotubes in the middle to support a beam.
There will be two courses of horizontal rebar running the length of the footer and vertical rebar every 16" for the stemwall.
On top of the footer, I'll make a stemwall, three gray blocks high. (24"'ish). In the stemwall, there will be vents per code.
The gray blocks will be filled with grout and into them set 10"L x 1/2w" galvanized anchor bolts to a depth of 7.5".
On top of the gray blocks will be a course of sill seal.
On top of that, a 2X8 sill bolted to the stemwall using the anchor bolts, nut and some sort of big ass washer .

The floor joists will be 16 foot long 2X10's spaced 12" apart running from the stemwall to the center beam (probably a laminated 6X6).
They will have a lot of free span, I am going by this.
http://www.engineeringtoolbox.com/floor-joists-span-d_1479.html

I am learning the math as I go (for example, I just learned that lumber dimensions aren't actual) so its possible there may be glaring errors in my plans or designs that seem stupid to experienced parties but I'm still in the learning curve.

Any constructive critiques, observations or suggestions welcome.

[MushCreek]

Looks like you're off to a good start. Just make sure that you are at or above code for your area. In FL in particular, holding the building DOWN is at least as important as holding it UP.

A few quickies- Make sure any wood in contact with concrete is pressure treated. Think about termite prevention, too. If you use typical tongue-and-groove floor decking, such as Advantech, bear in mind that the sheets only net 47-1/2" because of the tongue and groove. If you go exactly 24' wide, you'll end up a few frustrating inches short with the floor decking. It really annoys me that the decking is made that way! On my barn loft, I centered the decking, and had a strip on each side that was about 26" wide, meaning I had to waste 4 sheets of material. I should have just made the barn 4" narrower, but didn't realize it at the time.

[Redoverfarm]

In regards to termite protection.  If you are going to use a flashing bent 20 deg on top of your block to interupt the travelers you will need some type of protection for the flashing if it is aluminum.  There will be a chemical reaction between any pressure treated lumber and that metal and it will corrode.  Easiest fix would be to place a piece of 30# felt paper or ice/storm guard between the metal and the PT lumber.  Copper flashing does not require that gasket but it is costly $$$.

[Patrick]

There is a code for the anchor bolt spacing as well ,and if you buy the bulk packs they come with the nuts and washers.You can also add a bond beam on your top course of block by using either bond beam block or cutting the centers out.Using a skill saw with masonry blade works well add rebar in the cavity and tie your verticals to that grout or concrete the whole thing also best practice to tie your anchor bolts to where your verticals come out of footing could be code in Fl I don't know.

[Building]

A question about pressure treated wood.

Is there any reason to not use it for basically everything?
Sill, band joists, joists, framing, etc? Is it pointless in some applications, or overkill? Its not like it costs a whole lot more so if there's a legitimate benefit- even a 'maybe-if' benefit- I'll use it, but if its pointless, then I won't.

On the matter of termites, rural Florida, the termites here can gnaw through a schoolbus in an hour flat.
Any suggestions about how to employ flashing, what materials it should be made of and where to put it?

[Adam Roby]

In my neck of the woods, PT is almost twice the price and non PT. 

There has been some talk about the chemicals in PT wood not being so great for your health, so it should not be surrounding you in your habitat.  I will let the experts weigh in on that.  Personally, I would definitely use it on anything that will be exposed to the exterior (decking for example), anything that is in contact with cement, and anything that will be within 18" of the ground. 

[MountainDon]

The basic footing and stem wall looks okay.... the bottom of the footing should be 12" below grade to meet most codes. I did not read the FL section on that so that should be verified.


I would keep the PT outside the habitable space for the chemicals reasons mentioned. Another reason is that PT wood is seldom kiln dried after the chemical treatment and is susceptible to drying damage (twist, cup, warp...). 

The mudsill against the concrete = yes.  The building on top of that generally no.  Joists higher than 18" above grade can be regular non-treated wood, girders 12" or higher, unless otherwise stated in the code.

[flyingvan]

   Wear gloves whenever handling PT too---out West it's AZCA, a copper arsenate.  I think on the East coast they use more alkaline copper quat.  Either way splinters from it hurt a lot. 
   I think they pick the crappier boards to pressure treat----it hides a lot of defects.  Like Don said it splits easier.  It's perfectly fine to rest a house on the stuff   this is good termite barrier stuff to put down

[Building]

That looks like good stuff.
Where do you lay that down for termite resistance?

Also, very interested in what was noted above, about some sort of flashing for termite resistance, I assume between the sill and the foundation?

*ANY* other ideas in regards to termite prevention during construction are very much welcome.
Are there any sprays or coatings I can apply to the wood that will keep them away?

[Patrick]

I thought i remember an episode of this old house where they treated all the soil around the footing with some kind of spray then another treatment after the house was built. this article talks about it a little.treated lumber in our area is mostly garbage we joke that it is the piles of wood from the big box store that no one will but so they ship it back get it really wet and strap it tight and try to re-sell it again!http://www.ncagr.gov/SPCAP/structural/pubs/preconstruction.htm

[Adam Roby]

You may want to consider blue wood for the interior of the house rather than pressure treated.  Not sure what the cost is like though.
http://www.bluwood.com/

[Don_P]

Borate treated lumber (Bluwood) works for most wood eating insects and provides rot resistance, it is required in New Zealand, and Australia as well I believe. It is a great idea anywhere that has drywood termites or high susceptability to subterranian termites. I know Lowes can get it here special order, down there it should be more readily available.

Galvanized metal will hold up to treated sills if your not right on the coast, aluminum and treated is a no go. I tried the tarpaper barrier and bragged to an engineering professor about my technique... he was less than enthusiastic. The problem is the copper in the treated reacting with the metal in the flashing. Steel or aluminum react very readily with the copper, zinc not much, and copper not at all. One other way is vinyl flashing.

The pretreatment soil chemical is usually Termidor, applied by a pest control company. There is a well seperation distance, 75' IIRC but I'd stay further than that from my water supply with poison.

[flyingvan]

Sill seal goes between the masonry and pt wood.  The anchor bolts just poke through it.

[Patrick]

Does blue wood give you "The Blue Lung" after a few years , now if that blue house doesn't look inviting I don't know what does. Might want to use a fresh air system on that one.

[rick91351]

Does blue wood give you "The Blue Lung" after a few years , now if that blue house doesn't look inviting I don't know what does. Might want to use a fresh air system on that one.

I did a little research found this under 'blue lung' discounting the urban slag of pot with too many seeds and the inability for it to kick your butt..... 

The lungs contain tiny air sacs (alveoli), which is where oxygen is absorbed. These air sacs open up or expand with each breath.

The tissue around these air sacs is called the interstitium. In people with interstitial lung disease, this tissue becomes stiff or scarred, and the air sacs are not able to expand as much. As a result, not as much oxygen can get to your body.

Interstitial lung disease (ILD) can occur without a known cause. This is called idiopathic ILD. Idiopathic pulmonary fibrosis (IPF) is the most common of this type. 

There are also dozens of known causes of ILD, including:

Autoimmune diseases (in which the immune system attacks the body) such as lupus, rheumatoid arthritis, sarcoidosis, and scleroderma
Medications (such as nitrofurantoin, sulfonamides, bleomycin, amiodarone, methotrexate, gold, infliximab, and etanercept)
Radiation therapy to the chest
Working with or around asbestos, coal dust, cotton dust, and silica dust (called occupational lung disease)
Cigarette smoking may increase the risk of developing some forms of ILD and may cause the disease to be more severe.

[Building]

Two rough plans I need to do next are the walls and the roof.

1) I want the walls to be 10' high. Should I use cut down larger lumber and make 10' panels or is there any benefit to making standard 8'X8' panels and then setting them on top of some sort of 2'X2' riser footer? (I'd prefer a riser footer over a 2' header, given certain design considerations.)

2) I want a flat roof, no trusses, with a minor degree of pitch.
The general idea was a load bearing wall running right down the middle, which I would make 11' high, the ceiling beams running out towards the walls which are 10' high, giving me however much pitch 1' translates to over a 16' span.

Are there any special code considerations for flat roofs?
Are there any special design considerations for flat roofs?

I'll post concept pictures in a bit.

[Don_P]

1) I don't understand the question. A wall needs to run unbroken between points or planes of lateral support. In other words, don't build an unsupported hinge in a wall. The wall needs to run unbroken between bracing elements, such as a continuous wall between floor and roof floor to roof with no breaks in the studs between.

2) Below 3/12 many common roofing materials are not able to be used. As the pitch drops the likelihood of leakage increases and the cost of roof coverings increases. As a roof approaches flat the likelihood of ponding increases. If a roof ponds the weight of the ponding water deflects the roof members more, increasing the size of the pond, which causes more deflection, increasing the size of the pond more. A bad feedback loop, this is how many flat roofs collapse.

Does blue wood give you "The Blue Lung" after a few years , now if that blue house doesn't look inviting I don't know what does. Might want to use a fresh air system on that one.

No,
The blue in bluwood is simply a blue dye for consumer branding. The finishes you put on wood are more toxic by far. Some suit thought blue was sexy. DOT, the active ingredient in the product is disodium octaborate tetrahydrate, borate, google the msds. The field applied DOT borate is usually bora-care or timbor. Borate is a very low toxicity chemical derived from the element boron. They are using a pressure treatment process to get higher quanitites , more evenly dispersed .  The DOT that I use to treat lumber is the agricultural soil ammendment Solubor, used for balancing elemental boron in vegetable production... even in organic fields. This is chemically identical to the DOT used in bluwood. The other product they are applying to the wood is similar to Thompsons water seal, a water repellant coating.

[Building]

1) I don't understand the question. A wall needs to run unbroken between points or planes of lateral support. In other words, don't build an unsupported hinge in a wall. The wall needs to run unbroken between bracing elements, such as a continuous wall between floor and roof floor to roof with no breaks in the studs between.

Answer seems to address what I'm talking about.
So, to make a 10' wall, I can't use an 8' wall on top of a separate 2' footer.
I'll have to buy 12' lumber and cut it to the proper dimensions so all the framing members are one piece, the panels likely measuring 8' wide by 10' high.

2) Below 3/12 many common roofing materials are not able to be used.

What is 3/12?

[Redoverfarm]

Roofs pitch are measured in the amount of fall between the ridge and the eve.  ie; 3/12 pitch means for every foot you would drop 3".  4/12 is 4" drop and so on.  As an example if you have a rafter length of 10 feet there will be 30" drop in that distance.  I am sure Don_P is a better illustrater but I think you will get the idea.

[MountainDon]

This is a 4/12 pitch

[MountainDon]

There are many flat roofs in NM; actually most are not perfectly flat, they are 1/12 and 2/12. They appear flat as they are commonly used on pueblo style building where the walls have parapet tops. Older buildings often have almost flat and they are problematic, even in a climate that might get 8 inches of rainfall in a good year. The parapet walls are also a bad point. Their stucco cracks and leaks start down the wall and over the roof span.

In a more rainy climate I would definitely want a pitched roof. If you are building in an area with poor access I can see the potential difficulty in using trusses, getting them delivered being the main issue I suspect. They do have the advantage of being able to clear span the 24 foot width.

Perhaps a low pitch roof of the shed style could be workable. A shed roof is a "flat" plane that is pitched from a higher wall to a lower wall. I guess there is no snow load. With a mid span support that could be stick built in place.   With a 3/12 pitch and a 24 foot span that would mean having the high wall 6 feet taller than the low side wall though. 

[rick91351]

Our shop is a 5/12 or 6/12 shed roof.

[Don_P]

If there is a taller center wall, then a shed roof sloping down each way... you have a simple to build gable roof that is not too high.

[Building]

Yeah this isn't to precise scale, but it gives the basic idea



10' walls front, back and sides, 12' wall in the center, run roof beams from center load bearing wall to outer walls.

So, there would be some pitch but not a lot.
We have 0 snow, so that's not a consideration.
We're well above average rain, so totally flat is not an option.
Being Florida, big, flat exposures tend to give fits in heavy winds so flat intuitively seems better. I know the plans examiner chuckled when I suggested an A Frame.

[Don_P]

Too shallow for shingles or normally applied metal, you're at a 2/12 pitch. I'd suggest kicking it up to a 4/12 by lowering the exterior wall to 9' (garage studs) and raising the center wall to ~13'. Then you'll still have a low pitch but will be able to use more commonly available and economical roofing materials. Most low pitched roofs you see down there are 4/12's. Also notice how many low pitched hip roofs you see, this is also to shed the wind, gable end failure is frequently how hurricanes get into a house. One downside to low pitches is attachment of porches, they typically need to gable into the main roof rather than shedding off of a steep pitch... but in high wind areas they might not be the best idea anyway, the wind can get under an open roof with a whole lot of uplift force. Relatively shorter overhangs, ~2' max, also help in high wind, the lower corner of the overhang is another common place roofs start to come apart in high wind. Having just bought a roll last week, simpson strapping comes in 300' rolls. There is nothing wrong with running strapping over the framing from foundation, up and over the roof, to foundation on the other side. My in-laws place at Orange Beach had multiple straps up and over and has withstood the past 30 years just fine.