Contractor Talk - Professional Construction and Remodeling Forum banner
1 - 19 of 19 Posts

·
Registered
Joined
·
12 Posts
Discussion Starter · #1 ·
hello there

First time poster, long time lurker. Im in the middle of a basement renovation, Wanting to level a concrete slab, its a pretty well poured/finished slab, but its not super flat, and not as thick as Id likea couple areas we busted up and found 2" most of it seems like 3". So i was thinking Id take the oppurtunity to reinforce it with whatever i put on top of it. need topping to be able to go 1.5" to a feather edge. after looking around for a bit, it seems to me a product like Rapid Set Cement All could be a good fit. Im thinking prime with a product like Weld Crete, and use either 6" reinforcing mesh or a wire lathe where i can get it. I know it the spec sheet for cement all they say no priming necessary, but i figure it cant hurt...or can it?
The area i will need to do this in is about 400 square feet, broken up into a few rooms, thought the biggest area of concern is a 150 square foot bathroom thats getting a tile floor(would do a isolation membrane over new slab regardless). i dont have alot of experience with self leveling, though ive seen it done a number of times in much smaller rooms, and i know its not as easy as people think, plus its super expensive, so not sure its such a great fit.
The client had already ground and coated the slab in another part of the basement with an epoxy product that he got from a local masonry supply place, and it seems like a great way to damp proof an old slab before putting flooring over it. he would do this to whatever we do as well, though most likely not under and tile membrane, havent done research on thinsetting over epoxy, but guessing not a great set up.




any and all advice is much appreciated
 

·
Registered
Joined
·
12 Posts
Discussion Starter · #3 ·
What is your field of construction?


Mike
What is your field of construction?


Mike
Im handyman/ small general contractor, recently started working for myself after moving across the country with my wife. All residential. have many years of experience working for a large custom builder as a carpenter, but finding my experience has alot of holes, trying to take oppurtunities like this to learn
 

·
Registered
Joined
·
12 Posts
Discussion Starter · #5 ·
even with a high strength grout type product? Ive used alot of non shrink grout for filling steel column bases and stuff like that so im sortof familiar with how it behaves, not sure how similar "Cement All" is but it seems its essentially a structural grout product, and i could imagine it working pretty well for that with some well placed screeds laid out every 4' or so. i guess if it pops off after 6 months everyone, especially me, will be pretty bummed out. maybe i just fell victim to their marketing materials. i guess from what youre saying its the bond between slabs thatll be the point of failure, not the topper itself, is that right?
in your mind what is the best solution outside of jackhammer the slab up and have a flatwork guy do an awesome new one. maybe have the client do his fancy epoxy, then do a pourable leveller over it in controlled zones?
 

·
Registered
Joined
·
534 Posts
Couple of questions. Where are you located. Some times local conditions will change a answer. Is it a dry basement with no sump pump or signs of weeping or leaking. Age of existing slab and any cracking heaving. What’s the final finish desired, laminate, concrete, epoxy, carpet? Will raising floor level screw up stairs ?
 

·
Registered
Joined
·
156 Posts
I have an old detached garage that I poured new concrete over old. I wanted to replace the concrete but I also wanted to raise the hight of the floor. I decided to try pouring over the old. I put in a 6" slab with a rebar grid 2' OC. Its been there for 5 years and hasn't changed a bit from the day it went in.









'
 

·
Registered
Joined
·
12 Posts
Discussion Starter · #8 ·
Couple of questions. Where are you located. Some times local conditions will change a answer. Is it a dry basement with no sump pump or signs of weeping or leaking. Age of existing slab and any cracking heaving. What’s the final finish desired, laminate, concrete, epoxy, carpet? Will raising floor level screw up stairs ?
Mesilia,

thanks for the response- Im in Seattle. the existing slab is in a house built 1920, doubt the slab is that old but id guess between 30-60 years old, there was evidence of where the coal furnace was mounted so older than that. The existing slab is still in pretty good shape, nice smooth trowel finish, and RELATIVELY flat but not flat enough for tile, there are some cracks here and there with very minor evidence of dampness during extreme rain(ie all winter) but no liquid water ever according to homeowner, his epoxy solution seemed a good solution for moisture barrier when coupled with some strom water mitigation we did outside on the permieter, and was vetted by a couple different professionals that he consulted with. The existing slab is set on a pretty nice 4"-6" bed of compacted crushed stone, which we saw after cutting some out for underground plumbing. and for its age seems in decent shape. raising the floor too much is an issue, which is why we arent just pouring a new full thickness slab on top, but mostly because of ceiling height concerns.

thanks again for your opinions
 

·
Registered
Joined
·
12 Posts
Discussion Starter · #9 ·
I have an old detached garage that I poured new concrete over old. I wanted to replace the concrete but I also wanted to raise the hight of the floor. I decided to try pouring over the old. I put in a 6" slab with a rebar grid 2' OC. Its been there for 5 years and hasn't changed a bit from the day it went in.









'
that makes alot of sense, i bet you could set up a machine shop in there. did you do weld crete or etch the old slab? i guess you prob wouldnt have to if youre pouring a full 6" on top of it. wish we could do that in this place.
 

·
Registered
Joined
·
534 Posts
My thinking is that with the property values in Seattle and because of earthquake potential, age of structure and the current wetting of the existing slab I wouldn’t touch it unless it was for the full Monty. Remove existing slab insulate, water proof rebar as specified by engineer, replace sewer and water lines under slab and pour new slab.
Any bandaids that are being suggested maybe good for a year or two but in my opinion has the potential to bite you in the arse.


Sent from my iPhone using Tapatalk
 

·
Goin' Down in Flames....
Highwayman
Joined
·
6,612 Posts
You say it’s only 2”-3”. You’re putting in a bathroom, so that means under slab dwv

Probably no vapor barrier. (Sorry, didn’t read all the long posts with no paragraphs. 😳🤣)

Self levelers, and/or trying to get a thin topping to work is pricey and risky.

My opinion? Pull the whole slab and pour a new one. Get your plumbing in. Get a vapor barrier down.

Much easier, and I bet you save money anyway. 👍

Kind of like watching a guy (me 20 years ago 😳🤣) put 10 holes in a section of wall, trying to reduce drywall patching. 🙄

Easier to just pull the whole wall and rehang it. 👍
 

·
Registered
Joined
·
699 Posts
hello there

First time poster, long time lurker. Im in the middle of a basement renovation, Wanting to level a concrete slab, its a pretty well poured/finished slab, but its not super flat, and not as thick as Id likea couple areas we busted up and found 2" most of it seems like 3". So i was thinking Id take the oppurtunity to reinforce it with whatever i put on top of it. need topping to be able to go 1.5" to a feather edge. after looking around for a bit, it seems to me a product like Rapid Set Cement All could be a good fit. Im thinking prime with a product like Weld Crete, and use either 6" reinforcing mesh or a wire lathe where i can get it. I know it the spec sheet for cement all they say no priming necessary, but i figure it cant hurt...or can it?
The area i will need to do this in is about 400 square feet, broken up into a few rooms, thought the biggest area of concern is a 150 square foot bathroom thats getting a tile floor(would do a isolation membrane over new slab regardless). i dont have alot of experience with self leveling, though ive seen it done a number of times in much smaller rooms, and i know its not as easy as people think, plus its super expensive, so not sure its such a great fit.
The client had already ground and coated the slab in another part of the basement with an epoxy product that he got from a local masonry supply place, and it seems like a great way to damp proof an old slab before putting flooring over it. he would do this to whatever we do as well, though most likely not under and tile membrane, havent done research on thinsetting over epoxy, but guessing not a great set up.




any and all advice is much appreciated
Correct. You shouldn't do that.
 

·
Registered
Joined
·
12 Posts
Discussion Starter · #16 ·
Guys thanks for the input. its like one of those things where my brains heart knew the answer before I asked but was hoping to be wrong.
Mesilla- yeah youre right. I bet there are parts of Seattle where a 400 sq/ft house could be 900k.
Delta- ill try to clean up my grammar for ya.
thanks to all of you for the thoughtful replies. youve given me alot to think about.
 

·
Registered
GC
Joined
·
1,104 Posts
I did something very similar a couple years back. Ground floor slab sloped an inch and a half from front to back, about 600sf. 60 year old slab was in acceptable condition. I leveled it with levelquick, then installed a moisture barrier and floating floor.
The issue with doing anything like this is budget. Obviously the best approach is to remove and replace. In this case, the owner didn't have the money for that, so self leveling was the only option.
 

·
Registered
Joined
·
12 Posts
Discussion Starter · #18 ·
thanks for the reply-
youre definitely right, my last job i was exclusively working on super high end projects and budget really was never a consideration, only doing it right. Its been really educational since working for myself that regular people have money concerns and sometimes just cant or wont take your advice and do the whole enchilada, but still want the project done. its a tough balancing act, but im learning as i go.

For your project, were you happy with the results, and have you had a chance to check back in on it?
 

·
Registered
GC
Joined
·
1,104 Posts
thanks for the reply-
youre definitely right, my last job i was exclusively working on super high end projects and budget really was never a consideration, only doing it right. Its been really educational since working for myself that regular people have money concerns and sometimes just cant or wont take your advice and do the whole enchilada, but still want the project done. its a tough balancing act, but im learning as i go.

For your project, were you happy with the results, and have you had a chance to check back in on it?
The result was outstanding. A nearly perfectly flat, level floor. I had to work from the shallow end to the deep end, so I attached sleepers to the floor to set depth and keep the levelquick in place. Prep work is critical. Every hole the stuff can run in to has to be filled, the floor has to be clean, and you absolutely have to use the levelquick primer.

I haven't been back to look at the project, but I have spoken with the owner, no issues or complaints.

I've never once done a "money is no object" project. Most of my work is upper end for people with substantial assets, but they didn't get rich by throwing money away. There is always a budget.
 
1 - 19 of 19 Posts
Top