24x32 in Southern Illinois - New member.

[interex]

Tonight I spoke with a contractor who is coming out tomorrow to look at the piers and to discuss the specifics.

He also said he'll drill into the existing piers to insert 4x4 post base anchors (his words) so that we can do things right, for very cheap.

Also, I'm not sure I'm really too clear on what I'm wanting to do.

I want to build my 24x32 deck floor, which the contractor said my pier spacing and count is sufficient for that, so that's what I shall do first.

As you can see here,  http://countryplans.com/smf/index.php?topic=7477.40  TexstarJim is doing a 24x32 with less piers and more spacing than I am, so I feel mine should suffice.

As for the timber frame design... I don't want to build a timber frame home... I want to build my cabin's roof/rafters like this, with the two beams running down the top instead of 1, and make those two beams come down to rest weight onto the 2 center row of piers.

I'm going to show the contractor my ideas tomorrow and see what he says, but it really looks like this would work.

[MountainDon]

As you can see here,  http://countryplans.com/smf/index.php?topic=7477.40  TexstarJim is doing a 24x32 with less piers and more spacing than I am, so I feel mine should suffice.

I have a comment. But first; I'm not/not picking on TexStarJim, Jan Nicolaisen or any other member posted projects here on CountryPlans forum. I'm also not/not passing judgement on TexStarJim, Jan Nicolaisen or any other projects posted here.

My point is that I selected my signature line for very good reason.

This forum does not edit the forum content for correct engineering of the designs presented. This can be safely said of pretty much any forum that allows and encourages folks to proudly display their projects as we do. Nor does the display of any construction technique by any member convey any legitimacy to such presented techniques. We try, repeat try, to steer folks in directions that hopefully results in safer, higher quality project results. The "that looks about right" approach can not be endorsed by myself. I have learned a lot since coming on board and I continue to learn. The more I learn the more I realize there is still to be learned. "Seat of the pants" engineering used to seem to work well enough back when I had race cars in my blood; I'm not sure "seat of the pants" will get you anywhere in that field anymore.

For many things I try to recycle or re-use things I have laying about before buying new things. This goes for many things other than construction. After struggling through 65 years of life I could recount attempts made to save money by re-using "things". Some have worked fine, others I'd like to forget. Some simply were not worth the efforts and compromises made in their re-use. I'm sure some I have forgotten about.   Thank goodness for the passing of years.    I have a current re-purposing project I hope to display proudly and successfully in the next month or so.

Another good signature line would be something like... The fact that many buildings are still standing may say more about the conservative nature of strength of materials ratings than the design process, or lack thereof.

[Squirl]

I stopped commenting when I thought you were building a timber frame cabin.  I don't have much experience with that and the only knowledge I have is from helping a few builds and reading a book on it.  Don_P is and a few others have a lot more experience than many in that design.  Timberframes have many different engineering approaches to carry and distribute load and force than stickframes.  I thought your piers would connect directly to the posts to carry the load from the roof and the floors directly to the foundation.  As you can see the rafters connect directly to each other because much of the pull a part force is dealt with through cross beams with large wooden pins and joints.  These are very different principles from stick framing.  Spacing is fine in construction, but proper sizing and load distribution should go with it.

I am a little confused with the type of building you are trying to accomplish (stickframe or timberframe).  You are undertaking an ambitious project of both designing and building a large cabin from scratch.  If you would like to learn more on normal design standards for different types of building, I and many others are certainly happy to answer questions and point you in the right direction to learn more.  Pointing to another building and deciding that will work for you without knowing why is not an approach I would recommend.  TexasStarJim built with larger beams and larger posts than what you proposed. His building is only one story, with engineered trusses and beams throughout in a no snow, no wind area.  It is interesting that you point to his project because there are long discussions about sizing up and bracing beams and joists for that span.  A few have pointed to published guides that show how to determine what sizing/spacing you need.  If you do not feel you can use them, there are many plans for sale.  If you have a reputable builder doing the work and code department, you will probably need a detailed set of plans anyway.  If you have any questions, just ask.

[interex]

Okay, the floor/deck is not part of my concerns anymore, right now I'm trying to figure out the roof beams.

Here's what I'm trying to say/understand...

I could do my rafter beams similar to the timberframe home's image on page1.  Meaning since I have two piers down the center of the proposed area,  I could run support up the side wall to the peek and run purlin style rafter beams to the other side, where I would have 2 at the top instead of 1,  to run my rafters over.   This would distribute the top weight of the rafters not only on the outer walls, but the end 2 center piers.

I know it's really sounding difficult coming from me, and I can't draw for anything to try and show you what I mean, but if you take just the roof from the Timberframe image I posted, you might understand the type of roof I'm talking about building.

We've already decided to have the piers drilled and anchors inserted, to do away with the dek-blocks.  I've been reading, and reading, and calculating but the thing is, over half the projects I've read through do not follow the guidelines for standard building rules/codes, so I do understand that a lot of people do build without following them precisely.

[dug]

I'm not familiar with that roof system so I really can't comment on it but I think it would be a lot simpler to use a single ridge beam. You mentioned you are not a carpenter and as a first time builder myself I can testify that even a simple design is plenty challenging. There are ways to spread the load from a single beam to the foundation you will have (pretty sure), and some really good people here that could probably help you with that.

I've been reading, and reading, and calculating but the thing is, over half the projects I've read through do not follow the guidelines for standard building rules/codes, so I do understand that a lot of people do build without following them precisely.

No doubt about that, but I (and others I bet) have done some things on my build that I've come to regret after learning more on this incredibly informative site. Folks here don't judge but will shoot from the hip.

[Squirl]

I don't see why you couldn't run two ridge beams instead of one.  I assume the 8 ft in between the two ridge beams would need a rafter tie and a ridge board still.  Again, just like a one ridge beam the load has to be carried directly to the foundation.  You can use the beam code chart to calculate the proper sizing/spacing of this too.

  I've been reading, and reading, and calculating but the thing is, over half the projects I've read through do not follow the guidelines for standard building rules/codes, so I do understand that a lot of people do build without following them precisely.

No doubt about that, but I (and others I bet) have done some things on my build that I've come to regret after learning more on this incredibly informative site. Folks here don't judge but will shoot from the hip.

Mountaindon may not want to single any members out, but I will.
Take this one for an example.

http://countryplans.com/smf/index.php?topic=7305.0

This member wanted to do something "different."  To go with another method that was easier that he had seen in an old book.  He also traded quality and normal design for expedience.  By the 3rd year the foundation has already shifted.  He will be lucky if it lasts 10-15 years.  Try not to learn the hard way like this moron.

[Don_P]

And I was thinking "Geez take it easy on the poor guy"  ... we are our own harshest critic sometimes.

There's nothing wrong with a principal purlin common rafter roof, look in many older barns. The aisle was down the center with stalls on each side, this is how they were supported. The "problem" I see with using that system here is that those purlins will need to be supported through both floors on posts down to the footings. It's going to really limit your design options inside.

This is another option to throw into the mix to think about.
I've supported the main floor on your existing piers and the roof is a "cantilevered attic truss" that spans the full 24' and bears on the outer walls. The "room" downstairs is entirely open, walls can be anywhere. The upstairs "room" is drawn at 16' wide and has about 10' of width at 8' high.


If it were mine there would be a full perimeter foundation to stabilize and support the structure above and the center 2 rows of piers would be used to support the main floor girders. There are more options there. I would not proceed with any work until the plan is much further along.

[interex]

Okay, sorry guys been gone working a while.

We have planned a different route and I'm looking for opinions.

Would a 24x32 cottage be supported well enough on 4x4s or 6x6 post piers?

To recap, I have 20 total piers.  4 rows deep of 5 piers per row totaling 24Lx32W.

My next question is, would running my 2x10 (or 4x10) floor beams be better anchored on top of the post piers or anchored to the face/side of the post piers?

[John Raabe]

I agree with Don_P's suggestion of the attic trusses. Also, with a house of that size and in tornado country I would have as much weight bearing as possible go to a full sized and anchored perimeter concrete foundation. The piers would work great for the interior floor girders.

When doing girders that support the floor joists you want a solid 4x4, 4x6, or 6x6 (depending on the size of the girder) directly under the girder and attached with an anchor such as these: http://www.strongtie.com/products/categories/post_caps.html



If you finally do use the pier and beam for your perimeter foundation you will want additional diagonal bracing (4x4s?) as well. Also some way to tie the posts into the buried concrete piers. Tie all the major parts of the house together with straps and anchors (foundation, floor, wall and roof). This will give you more rigidity and protection against uplift.

[interex]

After talking with a few contractors, 1 said we could use the piers to do a pier and post build with 4x4 posts anchored to the piers using 3" by 1/8" angle iron, and with the amount of piers we could get away with using 4x4.  Another said the same thing except using 6x6, but said the 2x10 or 4x10 beams could be bolted to the face of the post instead of on top to reduce any front to back movement?

I am going to use my existing piers with posts and anchors but by reading and consulting, I am unsure of the post sizes and how to anchor my wood beams to my posts, and if I should do my joists inside the beams on build them on top, if that makes sense.

[Don_P]

Do not bolt to the face. The bearing area for the entire house load is concentrated on the upper half of the bolt(s). The steel can take it but the wood can't. Sit the bottoms of beams on something with broad contact area to avoid crushing and splitting.

4x4's are for mailboxes.

A pressure treated framed and PT plywood skirt wall connecting the posts would give a great deal of lateral bracing.

[interex]

Okay, you're not really giving any answers.  You said 4x4 is for mailboxes, does that mean I should use a 6x6, 4x6, what?

Giving direct answers to questions helps a lot.

[Squirl]

I thought that was your original plan to do 4x4 with a 4x10 across the top?  Don_P knows the science of building better than most.  He has forgotten more than I know.  The best I can do is point you towards published guides of minimum safe sizing.  Are you going with a stick built this time?  If so, please refer to the code guide posted in my original post.  It shows how to calculate how big the beams have to be and how much wood they must bear on. I would use caution with either of those contractors if they are suggesting a 1.5 story on a 4x10 over a 4x4 for an 8 ft span on a 24 ft wide building.

Also, you should refer to mountaindon's guide to planning.  Here:
http://countryplans.com/smf/index.php?topic=10675.0

Houses are designed from the top down.  Knowing how to size the foundation without knowing how and where the loads of the house will fall is just a guessing game.  

BTW.  I know a guy who did the "hang the board on the side" method.  He did it for a building with an 8 foot total width and spacing of 5'-10". It works fine for decks.  It is ok for sheds.  I would not recommend it on something you want to last.

http://countryplans.com/smf/index.php?topic=7305.0

[HoustonDave]

Interex,

Don was trying for a bit of pointed humor on the 4x4 comment.  Sometimes that doesn't come through in print (grin).

What he meant was "4x4 is for mailboxes, not houses" as in, he would never consider using posts as small as 4x4 for any significantly sized structure.

As Squirl mentioned, Don is probably one of the most knowledgeable people on here regarding structure sizing and strength.  I'm a newbie myself, and if Don tells me not to do something, I'm going to really sit up and pay attention.

In this case, he is recommending you use minimum 6x6 posts, and that you lay your pressure-treated beams ON TOP of those posts (not bolted to the side).  While the contractor is correct there is a concern with lateral movement, if you attach a treated plywood skirt around the perimeter (tying together the treated beams with the posts) it will stiffen the structure up nicely.  If you want a graphic example, I'm sure there are some folks that can show you pictures of similar.

As a fellow newbie, let me say that you are starting what I would consider a pretty aggressive first attempt. 

If you can, I would start by building a smaller structure, say an 8x10 shed at the site.  This would help you get a feel for what you can do, test out how well you understand the techniques, and also how much time, stamina, and patience you have.  I am going that route. 

I'm not telling you that you can't do it successfully, but frankly it sounds like you are trying to teach yourself design AND customize the design on the fly.  That is a lot tougher and more complicated than most folks realize.  You would probably be better off buying a complete design and NOT trying to tweak it, or paying someone to make a custom design it for you, so that you can focus just on building something guaranteed to last.

[interex]

Okay, so with 6x6 posts, is 4x10x32 big enough for beams?

Should they be 6x10x32, maybe even 4x12x32, or 6x12x32 ?

Remember, I have 4 rows of piers running 32 feet, with 5 piers per row totaling 20 piers, with about 8 feet between the center of each pier running the long direction (32'), and 8 feet between the center of each pier running the short direction (24')  I keep being told this is overkill but if it's overkill, wouldn't it be used in any advantage?

Reading on here, so many people are using so many different sizes for very similar builds/projects.

I'm asking questions to understand what people think, to know from people who have experience.

[MountainDon]

I've lost track of what this foundation is supporting. A refresh on the current plan would be good. Snow load for roof (available at county building inspection department)? Full upper floor or just sleeping loft? Roof type; truss framed or standard rafters with ridge board or structural roof ridge beam or what? These choices will affect the foundation design.

Someone pointed out earlier that design begins with the roof and from there goes down one level at a time. That is bang on! Design also takes into account special things like; library shelves full of books, king size water bed, mega sized gun safes and refrigerators, hot tubs, extra large bathtubs, weight/exercise machines, stone floors, etc.

Lots of folks do different things on projects that appear similar. Some of them have done a better job on design than others.

So without knowing what is to be supported choosing foundation member sizes is a crap shoot. I don't have the time to re-read the entire thread to try to figure out what the upper levels to be supported by the foundation are.

With all that said, a quick look at IRC Table 502.5(1) it would appear that for a structure with two floors with center supporting beams (only one down the center of each) and a roof resting on the side walls with 30 pound/sq ft snow ground load, the outside beams should likely be built up from (4)2x12's in order to safely span the 8 foot distance. The center two beams could likely be smaller if they were just supporting average interior loads. If they are supporting some sort of load from the roof then my guesses are out the window and an engineer could provide the best/safest answers.


I don't mean to sound harsh, but anyone needs the facts to stand a chance at providing valid advise and there are so many projects and questions it can get difficult to keep them sorted out.

[interex]

I plan for the center peek of my roof to be 14'-16' from the floor of the home.  I am looking at just a single floor, with a very small loft on one end, just enough room for kids to climb up and have a little bed/cot etc.

There won't be anything inside but a small couch, tv, table, fridge, 1 man shower, toilet, wood wall panels, peel and press T&G floor planks, etc... nothing too "fancy".

Also, I want to go with rafters instead of trusses.  I want to run 2 support beams along the roof from the center row of piers along the roof on both ends... to allow weight to be distributed to the center row of piers, maybe?   Like the image below.

[MountainDon]

I see. Are those planned 32 ft long roof beams to be supported only at the ends, within the end walls? Or would there be intermediate support posts as well?  If only supported at the ends then the footings under the end walls may have to be substantial. Getting into unfamiliar ground as far as my own experience.

[interex]

The 32' roof beams will have support inside, roughly 10-12' from one end, which leaves 20'-22' span the rest of the way through the open ceiling.

The reason why 10-12' is because this will be where the bedroom/bathroom wall is, which is also where the loft will be.

I wish I had a way to draw it out.

[UK4X4]

"I wish I had a way to draw it out."

Start with graph paper - squared paper to scale

Down load google sketch up for free, and use that - its 3D and relatively easy to do

I've only been using about 6 months

I use it for my outside views and then use Progesmart cad for the detail dwgs

there are some framing dwgs on my thread - just using sketchup, it gives you a clear view on how things will go together.


http://countryplans.com/smf/index.php?topic=9588.0

A ridge column to foundation will be a lot easier to do and complete the calculations than what you have dwn so far

[MountainDon]

Ditto what UK4X4 said about graph paper. One of the best planning tools ever invented. I use a drafting quality vellum for the serious drawings but start out with plain old graph paper for roughing out an idea. The advantage to vellum is its availability in larger sizes and the paper itself is very erasable; you can erase many times and erase fully without suffering any deterioration in the paper surface. Staples and Officemax carry it as do other like stores.

[MushCreek]

Once I get a plan I think I like, I often build a model at 1:24 scale out of 1/4" foamboard you can get at Staples. With a hot glue gun  it goes quick. I bought some cheap 1:24 scale dollhouse furniture on ebay to get a feel for the room sizes. Yes, I'm 57 years old, and I play with dolls!

[Don_P]

 The roof can be supported on purlins as mentioned before. The posts would be better if continuous from footing to top members, think post frame construction. The walls then brace the posts extending below.

[interex]

That is EXACTLY what I want.

That looks really good!  Thank you so much.

[interex]

I don't know how to edit posts, but I forgot to ask...

On the post beams, would the posts for the loft, and the supports for the purlins not be able to be put on top of the beams? 

Would I lost support on the beams if I did this rather than had their own individual piers?