AndyStandley

Floor Questions

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Hi,

I have been trying to make a viable floor for my house plans, and I have some questions about load-bearing walls. Mainly, I want to minimize my number of piers as well as the size of the members. But I don't know if load-bearing walls have to be exactly over the floor girders. I am attaching the floor framing and foundation with the interior walls referenced. Any help is greatly appreciated.

 

Here is a little context:

1. The local inspector told me he was uncomfortable with more than 8' between piers.

2. I was told it was best to put piers at all 4 corners of the stairs.

3. The 17+' span of the joists may be OK, but I was told it may be harder to get it in lumber. Mainly, I just want to make a common floor with simple materials, whether lumber or engineered products.

 

Thanks again, 

Andy Standley

9-pier foundation and floor.pdf

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Andy -- Your questions are really outside the scope of this forum and best answered by a structural engineer.

 

There are additional variables that need to be considered when designing a foundation/floor structure.

 

As for the 17' joist length, you will probably find 20' is the next common size, but you can use the excess for blocking, headers etc.

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 I understand and I have reached out to a structural engineer. But can you give examples? I thought the purpose of HDPRO is to allow motivated individuals to wrestle with and solve the technical difficulties in planning a house themselves. I do, however, see that HDPRO's automatic features are far inadequate, so that corrections are necessary. I did think the forum was to facilitate that learning process. I believe you even offer to correct plans?

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The forum is about using the software, not about what you are designing with the software.

 

Your engineer will give you what you need in the way of structure, and if you then need help implementing them into your plan, that's where the forum might help.

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I will see if I can help...with what I see in the attached pdf, two things jump out at me...but first a question or two...is this a ranch type single story house on a crawl space or basement...I will continue with that scenario in mind...

 

Your inspector is not empowered to stipulate the pier locations...your load bearing beam determines the maximum span...he can though be a PITA...signed engineered drawings trump his authority...

 

What are you using to carry the joists in the middle...a properly sized  steel beam can easily span 12 feet...

 

Have you considered using I Joists for the floor joists...a 11.5 inch I Joist can span over 17 feet and you can get them in 2’ increments up to 40 feet long...in my experience, like the roof trusses, the truss designers will size the I Joist correctly and provide engineered layouts

 

Hope this helps...any other questions please ask...

 

Regards

 

Rick

 

 

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Thanks. The house has a crawl space and a second floor/framed attic. The floor girders are triple 2x12, and I have my piers with no more than 8' span between them (although more center to center). I will have to look into the steel beam idea. I have already warmed up to the I-joists, especially for long spans in some parts of the ceiling.

My main questions are:

1. Does the main load-bearing wall down the center of the house holding the ceiling joists need to be exactly on top of the girder/pier system for the floor?

2. Does the stair need four piers at its corners? (it was an engineer that recommended this)

3. Do you see any simpler way to design the floor which may reduce member size.

 

9-pier foundation and floor.pdf

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I'm sure it would help Rick to have the plan file to review.

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Does the forum limit the attachments or something, because I cannot attach anything more.

OK, it seems to only accept PDFs.

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Are you getting an error?

 

There is a 25MB limit per upload.

 

It cannot be open in Pro, and you can try zipping it.

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16 minutes ago, AndyStandley said:

OK, it seems to only accept PDFs.

 

No -- images, zip files, plan files all work.

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54 minutes ago, AndyStandley said:

Thanks. The house has a crawl space and a second floor/framed attic. The floor girders are triple 2x12, and I have my piers with no more than 8' span between them (although more center to center). I will have to look into the steel beam idea. I have already warmed up to the I-joists, especially for long spans in some parts of the ceiling.

My main questions are:

1. Does the main load-bearing wall down the center of the house holding the ceiling joists need to be exactly on top of the girder/pier system for the floor?

2. Does the stair need four piers at its corners? (it was an engineer that recommended this)

3. Do you see any simpler way to design the floor which may reduce member size.

 

9-pier foundation and floor.pdf

Andy

1. Yes, otherwise you have an asymmetric load or shear plane on the pier

2. Yes, because you are running the stairs 90 degrees to the floor joists, all the joists butting into the girders at the stairs need to have engineered joist hangers...same thing for 2nd level ceiling joists

3. Not without having the entire drawing for review

 

Microlam beams can be used in lieu of either the 3 ply 2x12 girder or a steel beam. This layout screams for an i joist floor system. The layout from the supplier will show full length i joists spread across the length of the foundation with proper length doublers/triplers adjacent to and straddling the main joist. All the lap joints in the center of the structure are eliminated. If you have not ever used i joists, you will be amazed at how straight and flat the floor will be; provided you do your job installing them. Rim joist can be either engineered material or dimensional lumber. Layout plans and engineering info should be supplied by supplier...same for any trusses you use

 

Regards

 

Rick

 

 

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Thanks Solver and Rick. It looks like I had to close the file in Pro. The advice above will get me a lot further than I was. I'm attaching the PLAN just in case you have any ideas for a simpler way. I thought I might have to go with engineered products, and now I think they may be better anyway.

Andy

9-pier foundation and floor.plan

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8 hours ago, AndyStandley said:

Thanks Solver and Rick. It looks like I had to close the file in Pro. The advice above will get me a lot further than I was. I'm attaching the PLAN just in case you have any ideas for a simpler way. I thought I might have to go with engineered products, and now I think they may be better anyway.

Andy

9-pier foundation and floor.plan

Andy

Are you open to turning the stairs 90 degrees with the upper landing being in basically the same spot? Without room labels it is hard to determine your room usage thoughts.

What are your plans for the 2nd story...How do you propose to carry the floor joists. When using reference layers I do not see any bearing wall under the left side of the floor joists...if your plan is to only use the width shown, I would use attic trusses..just a rough calculation but you would end up with a room with the 8' flat ceiling in the center is about 8' wide...change the roof pitch to 9" and you pick up additional width at very little additional cost...

 

Let me know your thoughts and I will help you work on the design...

 

Regards

 

Rick

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I have been trying to figure how I can turn the stairs, and it won't be easy. They run with the length of the house, so without U-turning them, it will be a challenge. I am tempted to keep them and do whatever I need to do to the floor instead. I am adding a layout with room labels.

 

I am not 100% sure what you mean by attic trusses. I do want to maximize the space upstairs, and I am considering extending the exterior walls by a couple feet to help with that. I'm open to changing the roof pitch too. Whatever is better to maximize the space. I had already figured that I-joists were necessary for the 2nd story floor, because of the large span within the living room and kitchen area. 

Excellent help.

Thanks,

Andy

Room Labels for Rick.pdf

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Andy

 

I spent a little time turning the floor joists 90 degrees and adding structure to support the floor...you will find the design on the foundation level. See the notes for criteria.

 

Google attic trusses and you will see what they look like... a change in pitch to 10/12 or 12/12 will add considerable second floor space with 8' ceiling with no worries about long floor joist spans...the attic truss provides the floor joist system 

 

In looking at the room labels I assume the small room in the master bath is a water closet room and the room behind   it is a walk in closet...I do not see any closet space allocated in the other 2 bedrooms.

 

I poked around a bit and find some issues with the way the walls and roof are drawn. You have walls sticking through the roof among other things. It will take a bit of work to remediate these issues...not a problem.. converting the roof framing to trusses will help with those issues... I see the default ceilings are flat at 9'...are there any vaulted or cathedral ceilings desired...just need a bit of direction and some time...

 

If you would like to collaborate on the design...call me at 248 918 7973...my wife is recovering from surgery at the hospital so I have some time....I will take my laptop with me...

 

Regards

 

Rick

9-pier foundation and floor revised.plan

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Hey Rick, 

I looked up attic trusses and I like them. Yes, water closet with a walk-in closet. I need to add closets in the two others.  Also, yes, 9' throughout will be fine, I think. I'm currently downloading HDPRO 2021, and I call you in a few. 

Thanks a ton,

Andy

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