Getting a perfectly flat floor

[andywatson]

Hi, & thanks in advance for any advice.

I am doing a garage conversion, and want to raise the floor by about 6". I will be doing this by suspending joists in a fairly standard manner.

Does anyone have any tips for getting the joists in position so the floor will be perfectly flat, since the garage floor has a slope- so I can't simply measure up from that.

Andy

 

[kevnurse]

Buy a length of clear polythene tube that is the length of your garge plus a few feet. Create a U-tube along the length of your garage and the 2 miniscii will be exactly level with each other. Then run a tight piece of string along the garage between the 2 miniscii and fit the joists to touch the string.

 

[mattysupra]

Kev you lost me on that one and i know how to do it! Maybe a bit of an edit or clearer instructions might be needed!

 

[gcol]

To clarify... You buy or make a water level.
http://www.tradetiler.com/acatalog/water-level-220.jpg
You fill the tube with water. As water will always find it's own level you can make a perfectly level mark and work from that.
(By meniscii he means the water levels in each end of the tube - ideally, to read the water level correctly you need to read it from the centre of the tube and not where it clings to the edges but this will make very little difference anyway)

 

[JohnD]

Hello, Gcol, you're up early.

 

[gcol]

Not early here John. Stuck in my hotel room - daren't go too far from a toilet if you get my meaning. Coming home tomorrow.

 

[andywatson]

Brilliant idea, thankyou very much

 

[andywatson]

Just been mooching round some of the DIY online stores, and I saw the laser levels- would you recommend one of these?

I would be looking at a bargain basement one rather than some of the very expensive ones available!

 

[kevnurse]

There's no reason why a laser should not do the job. You need to make sure that the bubble is calibrated otherwise the laser beam will not be exactly horizontal.

 

[Symptoms]

Andy - laser levels are great bits of kit but 'you only get what you pay for'. Some of the cheap ones have limited beam range, lack intensity (so don't show-up in light areas) and can only be placed to work in one orientation (horizontal line). They often have a top & bottom of different sizes (big bum to hold batteries) and cannot be inverted. This may pose a problem when casting a horizontal so close to your existing concrete floor - you may not get the unit near enough to the floor; although you could get a level line higher-up then measure down.

If you do get one make sure it'll cast vertical and/or horizontal (it's the pivoting spirit level that causes this problem). Compact units are probably more useful/versatile to the DIYer.

 

[Deluks]

Cost of a laser level, vs cost of some clear plastic tubing, I know which I'd go for! A normal 6ft level and using regularised timber will do the job unless the span is huge.