Levelling problem new garage

[ianhutchinson]

Hi

Any help/advice would be greatfully received. I am currently building a large double garage, 19ft x 24ft the foundations are in and I have built up two blocks to the garage base level ready for laying the slab.

The problem is that down both sides the wall is showing level, using both spirit level and large piece of wood with level on top, but I purchased a cheap B&Q laser, set up in the middle of the base and took levels on each of the four corners. One side is showing a downward slope from back to front of three quarters of an inch and the other side a downward slope of half an inch, firstly is this acceptable over a distance of 24 feet and secondly what is the best way to ensure all is level before I pour the slab.

Or if this is okay what is the best way to level the first row of blocks when the slab is laid

Regards
Ian

 

[noseall]

a lot of garage floor slabs deliberately slope from back to front or towards the door, so that the floor can be washed with the water finding its own way out.

3/4" over 24' 'aint no hill 'o' beans.

you could almost get this out within the damp course layer as you have the opportunity to lay two mortar beds. two strong mortar beds at the low end and just enough mortar at the high end.

either way, you could easily get the masonry level by the time you get to wall plate.

 

[ianhutchinson]

a lot of garage floor slabs deliberately slope from back to front or towards the door, so that the floor can be washed with the water finding its own way out.

3/4" over 24' 'aint no hill 'o' beans.

you could almost get this out within the damp course layer as you have the opportunity to lay two mortar beds. two strong mortar beds at the low end and just enough mortar at the high end.

either way, you could easily get the masonry level by the time you get to wall plate.

Thanks, but what is the best / correct way to ensure thew first row of blocks on the slab are level

 

[noseall]

please stop double posting, of incur the wrath of the mod's. please read my post below.

 

[breezer]

please stop double posting, of incur the wrath of the mod's. please read my post below.

its only below now, might not be later, but yes I agree, stop double posting, it causes confusion

 

[ianhutchinson]

Thanks Noseall for your input

I can see the logic behind levelling four pegs in each corner and measuresing up to ensure the garage will be level but what would you use to do this spirit level or laser or some other method becasue in my earlier post the level showed level but the laser showed three quarters out, over a 24 foot length is three quarters of an inch acceptable

Regards

Ian

 

[noseall]

3/4" is acceptable and can be dealt with.

 

[Dashed]

With all considering, your problem may be the cheap laser itself. Usually it comes with a manual to check these sort of things. Maybe have a look there.
Also do a level check on your levels to make sure your level isn't out. A good laser will always be more reliable than your spirit level over distance

However I could also suggest using a water level - a thin length of plastic hose filled with water (with no air bubbles). It's a two man job. Start at one corner, i would think one of the front entrance corners and use that as your datum. Hold the water level in the hose at the height of the brick work and have the other person hold it on the next corner. Let the water find it's own level and get your offsider to whack a pencil mark on the brick wall. hopefully it will read the top of you brick wall but if it doesn't your not level - which isn't a huge problem as long as it isn't drastic. Run it around the other two corners to check. This is our third check on site if our laser and level readings differentiate.