Replace concrete or add to it?

[Titus]

I currently have a 20x20 metal building that was on my property when I bought it. I hope to replace it with a 30x60 metal building. The existing 20x20 slab is in good shape and is only about 5 years old. If it were you, would you tear out the old slab and start fresh, or tie in to it and add around it? Drawing of new footprint on top of old footprint attached.

 

[NUTTSGT]

How about building the rest of the area up and use the old concrete as footing for the new ?

 

[Kevin54]

Why spend more money to tear it out and put in new? If it is in good shape you can add to it. Just make sure the base is compacted real good beside the old slab (under the new) and have pins put in a regular intervals. When you cut control joints in the new, cut them to where they help disguise the old.

 

[Titus]

How about building the rest of the area up and use the old concrete as footing for the new ?

Interesting idea. The pad is already almost 2 inches higher than the driveway, so I am not sure if I want to take it much higher.

Why spend more money to tear it out and put in new? If it is in good shape you can add to it. Just make sure the base is compacted real good beside the old slab (under the new) and have pins put in a regular intervals. When you cut control joints in the new, cut them to where they help disguise the old.

I have spent a lot of time thinking of how I could add on to it and make it work well for me, but just can't seem to come up with any good ideas that work with the design of the old shop. Pictures of existing shop can be seen here. If you anyone has any ideas, I am more than willing to listen.

 

[djjsr]

How about this ........

 

[kblazer87]

If it is in good shape and easily tied into, then saving it is the way I would go. If the tie in is going to be a pain or the existing concrete or grade is questionable, then take I would take it out and redo it. You are only going to be saving about 5 yards of concrete at 4" thickness for the slab. That really isn't much in the total of your build. You will have to be the one to decide that for yourself though.

 

[cyamaha2007]

use it as a pad in front of your building. I wouldnt tie into it, ive seen to much crappy concrete in the last 3 years i do it for a living. Most crappy concrete is due to bad base or bad mix. Do you want to risk it heaving/cracking next to your nice new concrete. Who knows whats under it, was it reinforced, did they perform a slump test?

 

[rodnok1]

I wouldn't tear it out myself. I would make sure it is level, poss grind down edges to be flush with new slab. Make sure to compact the new area very well and tie it into the old slab by drilling into it and using rebar. I would consider NOT tieing it in if it was directly in middle of work area I would be using alot and any irregularities would jack my floor jack or creeper up.

 

[Falcon67]

I plan to add a 7 x 24' slab on the side of my shop for expansion. The "plan" was to just dig out the dirt, drill holes in the side of the existing slab, epoxy in some rebar and go to it. The existing slab sags on that side, so I may put a step under the edge for support. I'm sure the guy that poured it didn't do anything I asked as far as footings since the slab split in half after 10 years. Rule - be there when they set up and pour, take "no problem, go on your business trip, we'll handle it" as a warning LOL.

There's about 4.5 yards in your existing, that's $400~500 you save by using it. I'd use it.

 

[Titus]

Rule - be there when they set up and pour, take "no problem, go on your business trip, we'll handle it" as a warning LOL.

I work from home... eyes are always on workers at my house.

 

[NUTTSGT]

use it as a pad in front of your building. I wouldnt tie into it, ive seen to much crappy concrete in the last 3 years i do it for a living. Most crappy concrete is due to bad base or bad mix. Do you want to risk it heaving/cracking next to your nice new concrete. Who knows whats under it, was it reinforced, did they perform a slump test?

Not a bad idea there, if you have the room.

 

[Snap50]

There is no reason that you can't add around it.
We always limit slab sizes by using control and construction joints, so that would be the same as adding pieces.
Just don't make a long narrow piece without saw cut or formed joints to limit it's lenght to width ratio. Think of sidewalks; they always have joints to make square or small rectangle to limit shrinkage cracks.

 

[WNYflyer]

Maybe I missed it but is the new and existing slab intended to a be a floating slab on grade that does not support the building structure/columns or a continous reinforced structural slab that does act as the support for the building stucture/columns ? Two different animals. If a floating slab on grade probably not a problem to re-use. If it is to be a continous structural slab then could definately be a problem re-using.

 

[Charles (in GA)]

A red iron type steel building? or one of the corrugated ones? A regular "red iron" steel building needs a good sound footing and pier system designed for it. You need to talk to whoever will do the erection of the building and see what they think. I think you may run into an issue with depth and weight and strength of existing piers.

Charles

 

[Titus]

Thanks for all the feedback everyone. I like the idea of putting of starting the shop at the end of the old slab, but I just don't think I have enough room for that.

Maybe I missed it but is the new and existing slab intended to a be a floating slab on grade that does not support the building structure/columns or a continous reinforced structural slab that does act as the support for the building stucture/columns ? Two different animals. If a floating slab on grade probably not a problem to re-use. If it is to be a continous structural slab then could definately be a problem re-using.

A red iron type steel building? or one of the corrugated ones? A regular "red iron" steel building needs a good sound footing and pier system designed for it. You need to talk to whoever will do the erection of the building and see what they think. I think you may run into an issue with depth and weight and strength of existing piers.

Charles

I think you may have hit the nail on the head. I don't know enough about the design of the current slap or the design needs of the new building to be able to make a decision at this time. I'm just going to have to wait until I am ready and meet with the building company to discuss this.

 

[Daniel Dudley]

No way to add the new building to the back of the old one ?

 

[Titus]

No way to add the new building to the back of the old one ?

I have thought about it... I could extend the length of the current one and make it 20x60, but I am afraid that the 20' width would be really limiting.

Another issue with an add-on is that the current shop is not a kit. From what I was told, it was designed and welded up by a one man shop that did several buildings in the neighborhood but has since moved away. I suspect it might be a little difficult to find someone willing to modify/add on to something like this.

 

[little d]

titus, ya didnt say what ya planed to use the building for but, heres a thought, how about adding 40' wide by 30' deep next to it, tying into it. i know you will loose 10' of depth on the original 20', but if you can live with that, i'd think it would be the most cost effective way to go. just a thought, little d.

 

[the forgotten man]

See that you luckily are in TX so permits/engineering of the slab should not be an issue... other places want to see the engineering of the footings and rebar before the pour.... Even with no need for engineering the footings i think i would still pour all new for the building and use that slab for additional parking space etc.