Advice for 12x16 concrete porch slab and stain

[paulaner]

I am finally adding a screened porch to the rancher here in Maryland, and it may become a 3 season room someday. The porch will be 30" above grade, so I'll have footers, 8" block, and fill. I'm having this professionally done.

They will cap with 8" shoe block, fill with #7 stone, foam board insulation (outer edge) and 6 mill poly plastic for vapor barrier. Concrete will be 4" thick, 3500 psi, with fiber. They will use 1/2 inch rebar and wire reinforced.

The existing house (30 years old) foundation (block) only comes up about 12" above grade. I plan to ask him to replace the t1-11 siding on the house with 6" block where the new patio meets under the sliding glass door. Make sense? If not possible, do I use OSB and flashing?

Some of the new porch will be up against the existing brick chimney. Does this need to be tied together, or is an expansion joint better?

Lastly, we want to stain the concrete. We can have it pre-stained and poured for one solid color, or a broadcast die added after the pour. The other option (which SWMBO prefers) is the acid stain 28 days later

- from the internet pics these look to be the nicest floors. Any experience here? I hard fiberglass may show up when doing the acid stain, so we shold leave that out.

Ok -anyone with experience or expertise, let me hear it. I want to do this the right way, one time.

Thanks!

[trader4]

I'd go with the expansion joint material used on sidewalks and similar. Those two will always move slightly, each on their own, and that way there is room for movement without cracking.,

I had stamped concrete done on my outside patio about 15 years ago. Even the guy that installed it told the truth, which is that over time the top layer with the coloring eventually sucumbs to the elements. It held up for about 10 years, then it got to the point that I had to just paint over it with concrete paint. It still looks pretty good though. But now it's a uniform grey color. When originally done, it was stamped to look like gray stone, so there was color variation, which you don't have when painted.

But since yours will be enclosed, I think stamped concrete could be a viable choice. You can get it in a wide variety of patterns, from cobble stone, to brick, or store. It should last a very long time being shielded frrom the elements. Also, you do need to reseal it periodically. Outside I can get 2-3 years. Inside, again it should last a lot longer and it's not hard to reseal. I'd go with the solvent based sealer, both for the initial install and later too, if you can get it. Many states now ban it because of the VOC issues. It looks better and lasts a lot longer than the acrylic ones. I'd also ask about how many control joints they are going to put in. I'd definitely have one in the 16ft direction and probably one in the 12ft direction as well. Better to have that, than to have it crack randomly later.

But I'd also consider and price out going with just regular concrete and then tiling over it as another option.

[gfretwell]

I did acid stain on my driveway and it is holding up well. Inside you will be putting a heavy sealer on it to get that marble effect you see in the pictures. That finish will be as durable as the quality of the sealer and you may be resealing after a few years. The actual acid staining is not hard to do but it is nasty stuff so be sure to use the proper PPE and an acid rated sprayer. You want this done before you have any finish items in the room since it will stain everything it hits. Mask your brick work with plastic. It will eat right through rosin paper.

[dadiOH]

My experiences coloring concrete are minimal but for what it's worth...

1. Acid staining can look GREAT!...varying colors...patterns...swirly stuff. My father in law did it to his shop maybe 15 years ago (solid color, nothing fancy). I used poly paint. Mine is probably more worn looking but not much.
2. Broadcast dye. Don't do it. It *WILL* wear off. Even color through will eventually wear and expose the aggregate in the concrete but it is lots better than a topical coating.
3. If you want permanent and like the look, consider quarry tile on top. Not all that expensive and an easy DIY project. Another possibility is terrazzo; definitely not a DIY thing.

[paulaner]

If I go with "Integral Color" I assume it comes in the truck that way as a single mix - I will ask. Thanks.

[paulaner]

I agree with you on this.

I'll ask about the control joints. I don't think the wife wants a patttern in there, but if there are joints maybe it will help hide them. The sealer he quoted is solvent based (can't be used in California).

If it becomes a 3 season room, it may get a heating wire and tile someday.

Thanks for your thoughts.

[paulaner]

One option is hold off on the framing and do the acid stain 30 days after the pour. that pushes this project into December or January - brrr.

[paulaner]

I was planning on putting down a "solvent-borne" sealer. It says its developed for curing and sealing freshly placed concrete... where a clear matte or gloss based finish is desired. I was hoping this would help.

Yep - tile is in the future at some point.

Thanks for your thoughts.

[trader4]

When they did mine the guys added bags of coloring to the mixer on the concrete truck when it got here.

The solvent based sealer I used and highly recommend is Kure-n-Seal.

[bob haller]

you could just install radiant line as part of initial install, then add the heat source later if it needs it

[Home Guy]

Is this going to be a concrete pad-on-grade, or is there some sort of crawl-space under it?

What is the size (length x width) of the pad?

I'm trying to figure out if 4" is thick enough for a concrete pad (floor) over a crawlspace, or (if this is pad-on-grade) why you are building it like it's going to be loaded like a driveway (fiber + rebar

• wire). ?

[paulaner]

It's 12x16, and about 30" up. We will do footers to code, 8" block, and fill with stone. No crawl space.

I don't ever want to see a crack in this thing. We get lots of temperature swings in Maryland.

I think we will be skipping the fiberglass because we plan to do the acid stain. I heard that the fiberglass can sometimes be seen in the stain, so that's out.

[paulaner]

I could, but that wire is expensive. It might add another $1000 to the job. If I take that on a few years from now it might be easier on the wallet.

[bob haller]

I was thinking more of a buried in concrete PEX line, connected at some point in the future to a water heater and controls

[krw]

Inscrutable.

See!

[dadiOH]

Well 12' x 16' isn't very big but concrete *does* crack so make sure your footers are done well and that the fill is very well compacted. I don't know if a footer across the middle would help or not but it wouldn't cost much.

You mentioned that tile was in the future; that being the case, I wouldn't seal the concrete.

[paulaner]

Gotcha. If I was to install a boiler someday in the utility room, it's pretty far away from the porch. I think electric with a timer would be a nice solution. I did that in my basement office and really like it.

[paulaner]

First estimate for the concrete job is nearly $8.5k. I like the guy, and he comes with a good referral from a neighbor, but that seems a bit high to me. The area is accessible by excavator and bobcat, not far from the street. I already have the permit. There isn't any demo work to be done. Seems like straightforward job. I guess I need a

2nd estimate.

[dadiOH]

GASP!! OK, I'm old, I live in the past when a buck bought something, everything seems high to me but GASP again.

When we built our house in central Florida in late 1995, dug footers were $1.00/foot (plus concrete). The footer and slab concrete and finishing (helicopters) was just about $9,000 for 4800 sq.ft. Fill not included; nor is the (minimal) block to adjust foundation for slope of the land Ready mix was about $50/yard.

Now, here, add 40% for inflation; maybe a bit more, concrete may have gone up more. OTOH, people are crying for work.

Well, at $44.27 per square foot I'd be getting one. Probably several.

[Home Guy]

Your slab will take something like 2.4 cubic yards of concrete (if it really is going to be 4" thick).

The going rate for concrete is about $150 per cubic yard, maybe up to $200 if you ask for pigment or fiber.

So the cost of the concrete shouldn't run you more than $450 to $500.

Your quote must be chock-full of preparation work, excavation, fill, tamping, form setup, floating, etc.

The rebar will probably cost an extra few hundred bucks.

If you can do some, most or all the setup yourself (including buy and set up the rebar yourself, forms, etc) then your price will come down considerably.