Foundation, Footer and Slab from 1988-89

[rexpco]

I recently purchased land which has home that was started to be built in 1988 and never completed. The inspections were of footer, rough plumbing and slab ( Supported slab) which they all were inspected and passed by building official. The exterior walls are concrete block and have not had lintels poured or any vertical cells poured. Too nice of a job to discard.

In inquiring about finishing this building I was told by permitting official this:

You are going to need a single family resident packet to permit your home. We can give you that packet when you stop by. Also the architect or engineer will need to cerify that the slab is up to code for the home being built on it, as well as how much steel is in the slab, etc. They wil also need to certify that the plumbing in place is still okay. Hope this helps.

How does one say how much steel is in slab, unless we assume 1989 building code for Hernando County Florida was followed as it passed the inspection?

Can anyone point me to resource telling how in 1989 footer and slab was required to be built ?
Can anyone tell me current code for supported slab to be built ?
Is there any way to retrofit a slab to bring up from 1989 code to 2012 codes?
Know of any engineer who will certify this for me without too much expense ?

Thank you in advance for any help provided. I have worked construction most of my life and now for past 20 years have owned termite and pest control company.

Thanks REX

[Jerry Peck - Codeman]

Hi Rex,

First, does the building department have any of the old permit information, plans, etc.? I suspect the answer is 'no' because of what the building official told you, or did they check for old files?

Secondly, the walls having been laid up and the vertical filled cells, along with the lintel, never having been poured, makes the walls suspect for damage to the bond of the block to the mortar joints. Unless you are going to fill all the cells and make the walls fully grouted, there is a very strong probability that the mortar joint bond to the block has been degraded by the wind and the elements. My recommendation for the walls would be to not consider them as "Too nice of a job to discard." and, for your safety and that of your family, guests, and other occupants - knock the walls down to the slab.

That brings you down to the slab on ground (I believe that is what you are referring to with 'supported slab') and if it is suitable to build on.

First, you would need to design the house you are considering constructing, single story or two story, block or frame, to allow the size of the footing to be determined, then then the size, number, and location of the steel reinforcing bars in the footing. Then, an engineer with the proper equipment can determine the size and location of the steel in the footings - however, this is not cheap to do, but that would be the next step.

My guess is that the footing will not have the correct size and placement of the steel in the footing, with the end result being that the cost to correct is greater than the cost to remove the slab and start from scratch. Starting from scratch will no longer limit your floor plan to that of the plumbing.

An good plumber should have a pipe snake with a camera on it to check the plumbing which is under the slab. Being as the piping is PVC (which is not sunlight resistant) you will need to replace the above slab PVC, but the underground PVC should be as good as the PVC would be in any house of that age - and no one requires the PVC to be removed just because the PVC is old. The plumber could also do a leak test to make sure the underground plumbing does not leak. The camera will let them see that the underground piping does not have any bellies, dips, or rises in it as those cause accumulation of waste and blockage of the piping.

Current dead and live loads on the structure are much greater than they were in 1988-89, and thus the structure would need to be much stronger, which includes the footing, the slab, and the steel in the slab and the footing, also, the number and location of the steel in the footing and in the walls has changed in that time.

I can look some things up for you, as can others who have a collection of the old code books, but that is time consuming and all you will have accomplished is spending money to establish what you have, and then most likely that will not meet what will be required for today's requirements.

There is also the issue of the depth the footing is down below grade, which is the same as was required back then, except that back then, few people enforced the depth below grade.

Also, you would need to address flood elevation for the slab - which is most likely going to be higher than it was back then.

I would estimate that there is an 85% chance that after spending the money to check everything out, that the end result will be that you remove the slab and start from new.

I realize you think it "Too nice of a job to discard.", but trying to salvage that will most likely cost you more than removing it and replacing it, and then you would not have the same limitations placed on what you can build to make what is now there work.

I know that is not what you wanted to hear, but the least expensive way to proceed is to back up and start over fresh.

My answer would likely be different if that was a large condo building or old hotel, however, it is often less expensive to knock those down and start over than to try to retro-fit those to work as new with all of the new requirements.

[rexpco]

Building department only had record that it passed footer, plumbing and slab inspections which means it met code in 1989.

They had floorplan, electrical, heating, and plumbing plans, but nothing of the footer and slab plans. I'm assuming the amount of steel met requirement at that time so they should have idea whats there. (If I knew 1989 requirements it would help)

I see what you are saying about the wall blocks. I was hoping there was some way to retrofit or improve the footer and slab to meet the building dept's requirement. I'd like to keep from destroying and hauling this off, seems a terrible waste. I own several homes including a 1980's era house I live in and a 1945 era duplex which although doesn't meet todays codes they are causing no problem.

Is it possible to place footer surrounding current one which meets todays code, build wall upon it and roofing, thus using the old slab as floating slab (Similarly) Therefore using the plumbing as well ?


I wasn't planning on building and living in personally, just a project. I was wondering also if building a small cottage 600 SqFt (smallest county will allow) in the front of this lot and using the slab as greenhouse garden for personal use. Maybe that will fly with the building department. I agree that fixing may cost more than replacing, I can understand that. I'd just like an option to reuse rather than remove. I guess a variance may be required for that as exceeds square footage for accessory building.

Thanks,

REX

[Jerry Peck - Codeman]

[rexpco]

I like the idea of perimeter footer, column and pins bringing this slab into use. I'll speak with an engineer about this concept.

Another question, Can I save the blocks and reuse ? I'm not sure how hard it is to dismantle and clean...

I appreciate your quick advice.

Rex

[Jerry Peck - Codeman]

Rex,

When you knock the block walls down, there is no easy way to try to save the blocks as most will break when you knock them down. Additionally, you may be required to show that the concrete blocks are as good as new (they won't be) before being allowed to reuse them as any reused material must be proven to be as good as new material. You will have a hard time chipping the mortar off the concrete blocks so that they will lay up properly and get a full mortar bond.

I would just plan on biting the bullet and having the old concrete blocks hauled off.

104.9.1 Used materials and equipment. The use of used materials which meet the requirements of this code for new materials is permitted. Used equipment and devices shall not be reused unless approved by the building official.

[rexpco]

Thanks Jerry,
Why can't I just save the world...lol

I appreciate the service you have provided, I sent you lunch via paypal below.

Rex

[rexpco]

Jerry,
I spoke to the building dept this morning and they clarified what they want. They want engineer to certify that what is there (slab, footer)is sufficient for the structure being built on it, and also certify that the existing plumbing is okay.

Also everyone agrees to trash the blocks, much which you already stated.

It is up to engineer at this time to design additional pinned footers or certify whats there. County wants liability to be on engineer I assume.

Brings me to an additional request: Do you or someone you can provide me information on how a 1200 square foot supported slab and footer should of been constructed in 1989. (HERNANDO COUNTY SPECIFIC) Size of footer, steel amounts in footer, slab steel requirements, and vertical steel requirements. I'm willing to pay via paypal for a little time.

A brief description of my observations:
It is approx 32" from top of slab to top of footer.Footer appears to be 4" wider than blocks and about 8" deep where I dug. Slab top is about a foot above grade on lot. It has vertical cells knocked out at slab level showing what looks like 5/8 rebar on each side of doors, and windows and no more than 5' apart elsewhere.

Kindest regards,

Rex Wilkins

[Jerry Peck - Codeman]

[rexpco]

Jerry,
I agree I'm not so great at describing things. The item you refer to as:

1) the top course of block is chair block, the slab is poured into the chair block and keys itself into the chair block, the top of the slab is even with the top of the chair block

Seems to be the most accurate description. I drew a diagram quickly to show you how it is built.

About 32+ inches from footer to top of slab (4 blocks) the rebar is at each side of doors and windows about 4' apart vertically. Footer appears to be about 6-8" in debth but I havent dug completely.

Yes, I agree on difficulty in getting engineer to assume liability for work not his. I contacted a couple of GPR - Ground penetrating radar companies which stated this:

We appreciate you contacting us. This is one of the services we provide, as this happens often. We will scan multiple areas of the slab and footer and our engineer will write a report stating that the slab was built to code. He will not be able to certify that the slab will hold a specific structure as that is out of the scope. The county wants to know that the slab was built to code and we can either confirm or deny that this is the case. We can provide this service for $850. We accept MC/VISA and Amex or check. We do require payment at the times service is rendered.


As far as steel removed by workmen, This project was started by homeowner builder and he died after completeing this portion of home. I'm sure steel placed is there as there. As there is still 2 rows of steel in top lintel course of blocks. Of course we can't assume much...lol


I guess the whole solution is money...lol

Kind Regards,

RexSlab Representation.jpg

[Jerry Peck - Codeman]

Rex,

Your drawing is showing chair block (that is what I have always called it and always heard it called as the block is cut back during manufacture and resembles a chair).

Here is a manufacturer of concrete block shapes and they refer to that chair block shape as 'Cut Header': (place cursor over link, right click, select 'Open in New Window') http://www.specblockusa.com/downloads/f ... Uguide.pdf - scroll down 6 pages, pages are not numbered, to where it shows * 8" Units - Grey Block - Split Face * along the top of the page. The chair block, or cut header as they call it, is at the right end of the top row of shapes shown on that page.

You can see that when these blocks are laid end-to-end that the concrete will fill the block and the full height portion of the block simply serves as a form to retain the concrete when the concrete for the slab is poured.

Your drawing is quite nice, your drawing shows those little return ends and webs, and shows the concrete slab filling the open spaces between the ends and webs of the cells.

I am looking at my 1988 Standard Building Code, which was quite possibly in effect when that structure was started, and it is not much help as it states:
- 1302.5.2 Design of footings shall be in accordance with Chapter 16.
- Chapter 16 Concrete Construction
- - 1601.1.1 Structural members of reinforced concrete, including prestressed concrete, shall be designed and constructed in accordance with the provisions of this chapter and ACI 318.
- - 1606.1 General
- - - Details of reinforcement shall comply with the requirements of this section and ACI 318.

Then Chapter 16 does not address the number, size, or location of the reinforcement. So that was not much help.

I also have, somewhere (but I could not find it) a copy of the SBCCI (Southern Building Code Congress International - which produced the Standard Building Codes) SSTD10, which was initially named "Deemed To Comply" as it was a manual of prescriptive this-is-how-to-construct-the-structure-and-if-done-this-way-then-the-structure-is-deemed-to-comply-with-the-code. After a few years, the "Deemed To Comply" name was dropped. As I recall, that addressed the typical footing as I recall it has always been addressed ('always' meaning going back to first memories of construction), and it was 'always' two #5 bars in the footing on chairs supporting the steel at least 3" above the earth below because the minimum concrete cover over reinforcement steel in direct contact with earth is 3" of concrete.

Most normal footings I inspect today are still using two #5 bars in the footing on chairs supporting the steel at least 3" above the earth for minimum 3" concrete cover. These are designed by engineers and most regular houses use the same two #5 in the footings. Special high load footings and various other footings may have three #5 bars, but the typical footing is still specified as two #5 bars.

I would say with 95% certainty that those footings would most likely have been required to have two #5 bars in the footings. I wish I could find my Deemed To Comply, but I can't find it right now.