Floating Floor prep on concrete slab.

[Salem]

Hi, I'm looking for some ideas on how I can tackle floor levelling over multiple rooms. I've purchased floating floorboards which I know allows for up to 3mm tolerance over a 1m span. We've just taken on the monstrous task of removing a tiled floor over 45sq metres. The tile sat 35-38mm high off the slab on a sand and cement bed and after removing all the base it's become quite obvious that the floor is not level with peaks and troughs. Can somebody please advise what's the best means of achieving this. I cant imagine dragging a 1m level across the entire slab is the best means. I can grind down any high spots I locate but how do I know that this high spot is not lower than another part of the room. Hope that makes sense. I also have multiple rooms to do which adjoin with a common hallway. Would be nice to know how to tackle that and if its suitable to just poor floor filler in one room and be able to continue the floor levelling into the next adjoining room. I plan to use self levelling compound at this point but will make that call when I check out the floor levels a bit more closely. Thanks..

91702

[Larry McCully]

Hi Salem, well its a bit of a task, but it can be done. I find the best way of finding levels is with a laser. But since you wont have one of those, get youself a 3mt straight edge. you can use a length of the flooring as a subtitute. Starting in any room, Hold the board on its edge and place it on the floor. Mark with a piece of chaulk or marker pen where it touches the floor. Then where there is a gap mark at random places along the concrete a reference to the size of the gap. Example: if you think it looks like a 3mm gap then write a 3 on the concrete at that spot. I normally space my reference marks about 300mm apart. Then move the straight edge down about 500mm and repeat that reference process again. Move down the entire length of the room, once you have done that row, move over and do another row down the room. Repeat that process for each room. When you are all finished, you will see a whole bunch of marks and depth references. Then simply join the marks where they touched the straight edge. You will see a outline of the Hollow apear. That is where you pour the leveling compound. And screed it out to a feather edge.If you have high point. Check first that that are actually at the same height as the normal floor height. Its a task for a experienced person. It can get a bit confusing sometimes.
Hi, I'm looking for some ideas on how I can tackle floor levelling over multiple rooms. I've purchased floating floorboards which I know allows for up to 3mm tolerance over a 1m span. We've just taken on the monstrous task of removing a tiled floor over 45sq metres. The tile sat 35-38mm high off the slab on a sand and cement bed and after removing all the base it's become quite obvious that the floor is not level with peaks and troughs. Can somebody please advise what's the best means of achieving this. I cant imagine dragging a 1m level across the entire slab is the best means. I can grind down any high spots I locate but how do I know that this high spot is not lower than another part of the room. Hope that makes sense. I also have multiple rooms to do which adjoin with a common hallway. Would be nice to know how to tackle that and if its suitable to just poor floor filler in one room and be able to continue the floor levelling into the next adjoining room. I plan to use self levelling compound at this point but will make that call when I check out the floor levels a bit more closely. Thanks..

http://www.renovateforum.com/attachments/f203/91702-floating-floor-prep-concrete-slab-laminateflooring.jpg

[Larry McCully]

Another way of getting a level, is to use extra layer of underlay at any point you come to during installation that you think needs it.Cut up some strips as needed.

[Salem]

thanks for the info Larry, would love that laser but will settle for the straight edge. That all makes sense to me. Its all a little scary particularly pouring self levelling over a floor that we just demolished but I'm keen none the less. The trickiest part for me is probably trying to work out what is in fact the normal height of the floor but I think once I use your method explained I should have a fairly good idea. If I move through a room in one direction trying to find level do I have to rotate the straight edge 90deg and do another swipe of the room or is that unnecessary overkill? I assume I can take the same approach for a 800mm hallway using a 3m straight edge. Is there ever a need to consider the level in the last room to be done before commencing work or is it best just to attack one room at a time?

[Larry McCully]

If I move through a room in one direction trying to find level do I have to rotate the straight edge 90deg and do another swipe of the room or is that unnecessary overkill? No its not nessesary to project in the opposite direction. You will get what you need from going in the same direction. Then once youve done that row, move over and do another row. You will se a pattern emerging.


I assume I can take the same approach for a 800mm hallway using a 3m straight edge. Is there ever a need to consider the level in the last room to be done before commencing work or is it best just to attack one room at a time? Yes , same for the hallway, but use a smaller straight edge.

[Salem]

3 of the most recent posts from me in this forum. I think too much. just a perfectionist and very curious to learn all there is to know. I managed to pick up a 3m straight edge and have finished my kitchen prep so I'm all ready to go and suss out the condition of this floor. I was looking back on your advice Larry and I've interpreted it as grabbing my straight edge. Marking where the straight edge makes contact and writing the down the gap of the depressions every 300mm along. Once I've finished marking along the 3m straight edge slide it horizontally 500mm and continue the process all over again until I hit the end of the room then start a new row. I hope I got that right.

One thing that's really playing on my mind though is whether I'm supposed to place a spirit level on the straight edge and getting this level before marking the depressions in the concrete or whether I disregard the use of a spirit level and just slide the straight edge around the floor. I was always led to believe that it was more important that the floor was flat as opposed to being level. There are some very notable depressions in the floor that I was going to fill with self levelling to bring closer to the surounding area but there is a downward slope to the back of the home that I'm wondering may make this method a little tricky causing me to fight with the self levelling compound to keep it within the depression.

[shauck]

3 of the most recent posts from me in this forum. I think too much. just a perfectionist and very curious to learn all there is to know. I managed to pick up a 3m straight edge and have finished my kitchen prep so I'm all ready to go and suss out the condition of this floor. I was looking back on your advice Larry and I've interpreted it as grabbing my straight edge. Marking where the straight edge makes contact and writing the down the gap of the depressions every 300mm along. Once I've finished marking along the 3m straight edge slide it horizontally 500mm and continue the process all over again until I hit the end of the room then start a new row. I hope I got that right.

One thing that's really playing on my mind though is whether I'm supposed to place a spirit level on the straight edge and getting this level before marking the depressions in the concrete or whether I disregard the use of a spirit level and just slide the straight edge around the floor. I was always led to believe that it was more important that the floor was flat as opposed to being level. There are some very notable depressions in the floor that I was going to fill with self levelling to bring closer to the surounding area but there is a downward slope to the back of the home that I'm wondering may make this method a little tricky causing me to fight with the self levelling compound to keep it within the depression.

I think this is what Larry means. 92134

[Salem]

Thanks shauck, that's how I imagined it to start with. Must be over thinking things. Now I just need to understand whether I need to use a spirit level on the straight edge to bring it level before doing my markings or whether to just lay it flat on the floor and mark in this manner. Aiming for flat as opposed to being level.

[Larry McCully]

All Good Salem, one have the idea first go. Once you have marked up the touch points, just join the dots with chaulk. A Nikko goes dry and pencils wear fast on concrete, marker paint is good. Anyway join the dots and you will see the outline of the hollow bits. With the depth indicators, you will be able to get a basic idea of a average depth thickness so that you can purchase the amount of leveling compound needed. When you are about to fill, just pour the filling into the deepest spot of the hollow and with your straight edge, trowel it out to a feather edge. Dont worry about the flakey lumpy bits at the edge, when the fill is almost dry, you will be able to broom it of and at the same time use a short lump of wood, some thing as flat and as solid as timber flooring. use it as a sanding block on the edges to feather it . Do all that at 3/4 dry time or hard enough to sand of. Not dry, it wont budge when dry.
Thanks shauck, that's how I imagined it to start with. Must be over thinking things. Now I just need to understand whether I need to use a spirit level on the straight edge to bring it level before doing my markings or whether to just lay it flat on the floor and mark in this manner. Aiming for flat as opposed to being level.

92149

[Salem]

Champion, you've just answered the other thought I had regarding feathering it out. looking forward to this.So with regards to using a spirit level on the straight edge, can I assume you dont worry about using it?If I dont worry about using the spirit level then I've only got a couple mm to worry about filling. If I use the spirit level on the 3M straight edge I have to raise one side which then opens this up to filling with a 5mm gap. Just wondering if I throw the spirit level out the window and not worry about it. The slab has a gentle slope to the end of the room so there are some areas where the straight edge sits nice and flat but gently slopes down to my external wall.

[Larry McCully]

Thats scary, if you dont mind the gentle slop but you want the hollows filled then go for it. If you think that you want to get a level floor, then apply the same principle, Tape the spirit level to the straight edge, suspend at the low end, measure the depth and take it from there. Sometimes its needed to do a flood coat to get the levels up. It does make for a better floor. I suppose its worth the effot at this stage, so that you can enjoy the future.

[Salem]

I'm going to have to put some deep thought into this. Thanks heaps for your help Larry. I totally get what you've said and it's been really great to get some insight into how to tackle these issues. I used a spirit level and straight edge to start with marking it out along the way. Unfortunately not a great result. The only point that actually made contact with the floor was the corner on one side. Over a span of 3.4m it dropped 13 to 15mm over the entire floor. This was pretty consistent. Then I decided to try along the hallways. Same deal drops 10mm. Then I spun it 90deg to try and understand the scenario a bit better and whammo would you believe not level again. Crazy, looks like there might have been some sanity to the existing 38mm high tile that was on the floor. I did however look at the height of the existing skirting along the hallway and it appears that the skirting followed the concrete slab and not a level. Will invest some more time into this on the weekend.

[shauck]

When you stand on it and look at it, can you tell there is a 10-15mm fall across the floor? Is it noticeable to the senses? If you decide to leave the fall and are putting in a kitchen/other and need level benches, all you do is level the kickbox/adjustable feet on cabinets to level. If you will have a dining table, that may be noticeable, depends if you're prepared to butcher it's legs or pack somehow. Sort of depends on use and how badly you want it level. How much would it take to fill it to level? $$?? A positive side of filling to level, you probably don't have to worry about the dips/hollows as they'll all get filled in the flooding?? I've never used the stuff so don't mind me too much, just thinking out loud.

[Salem]

yeah shauck, I dont think I can make a call on whether it's noticeable. I'm too intune with what's going on. Been renovating a while now and all I see are curves. When I started renovating I had this grand idea that all the walls would be straight and level including floors, doors, windows etc... I quickly threw that theory out the window. I think I could probably get working on flattening the ground so its on a gentle slope but it makes me think a lot more about this stuff like will the kitchen kickboards sit flat against the floor, and when I sit down on the dining table will my dinner slide off the table. (OK not quite). Not a great scenario. Real shame, particularly after busting our backsides to dig up the existing tiling which was a mammoth of a job.

I think I might have to make some calls and bring in a pro on this one to give us a hand. Real shame. I'll still look into it further but I know the pro's will know how to handle this better. thanks for everyones help.

[shauck]

If it was me, I'd just fill the hollows and get the floor flat and not worry about the tiny slope. If the floor is flat, the kicker faces will be flat to the floor but just may need to be trimmed along the bottom edge to suit. Use adjustable legs rather than kicker boxes. Seriously, you should see my house (1890's miners cottage). My floors are all over the place and some walls are not plumb and are nowhere near square to each other or to the floor. Being a miners cottage, I figure it's acceptable. If 10-15mm was all I had to worry about, I'd be pretty happy, unless it was a new build.