Question :

I'm halfway up around a four walled bathroom, or five walls (including an external corner) as one wall has a box wall covering water/waste pipes etc. Top of all tiles are spot on level.
I have a datum line I marked around all walls above the door frame (the only area where all walls meet) I used a 1.2m level and marked the line that meets perfect.

I have taken measurements from this datum line to the top level of tiles at different points and have found a discrepancy in measurements of 3mm yet everything is registering as level.

I intend to finish above the bathroom door but my concern is the grout lines meeting, how do you guys make adjustments when you are approaching that point to make sure your grout lines meet spot on?

Edit* I have a 2mm grout line and tiles are being fixed brick bond.

Thanx Jimbo

Originally Posted by Jimmy Boy

Question :

I'm halfway up around a four walled bathroom, or five walls (including an external corner) as one wall has a box wall covering water/waste pipes etc. Top of all tiles are spot on level.
I have a datum line I marked around all walls above the door frame (the only area where all walls meet) I used a 1.2m level and marked the line that meets perfect.

I have taken measurements from this datum line to the top level of tiles at different points and have found a discrepancy in measurements of 3mm yet everything is registering as level.

I intend to finish above the bathroom door but my concern is the grout lines meeting, how do you guys make adjustments when you are approaching that point to make sure your grout lines meet spot on?

Edit* I have a 2mm grout line and tiles are being fixed brick bond.

Thanx Jimbo

I will always leave the cuts off to the ceiling, then on approaching the door casing, place a batten on top of last row from ceiling from point to pont and measure cuts to suit over the door....3mm is very easy to lose in door width.....Gaz

if its only a few mm you should be able to pigal it over the door:Pete

i dont want to sound stupid, but i dont quite get this....whats the point of the datum line ?

A datum line is the most wonderful thing.

Originally Posted by m4ubs

i dont want to sound stupid, but i dont quite get this....whats the point of the datum line ?

Is this a question regarding this particular thread or is it a new question entirely?

Grumpy

It's a pencil mark level line all around the room. To take guide measurement readings off.

A datum line is basically a level line around a room from which you can take measurements from and find out high/low points on the floor and ceiling.

yeh but isnt he saying that he marked the datum line above the door frame coz all walls were meeting. He started tiling from some point below the line and all the fixed tiles are level...but when he measures from the datum line to the top of the fixed tiles in different places there is a 3mm discrepancy ? whats the point of the datum line ? i just dont get it.....im confused, lol
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if he uses the datum line to measure downwards and fix tiles, then he might getting them kinda readings coz hes not holding the measuretape straight ? slightly unlevel n ur not gonna get a correct reading r u ? or am i still confused ?

Maybe he used the top line as his datum and then dropped a line down the bottom somewhere as a starting point, just using the top line for his measuring.

Possibly as he has dropped his measurements his line moved for some reason at one point or another.

Grumpy

When using datum lines its best in my opinion to use a staff and not a tape measure. Tapes tend to be unreliable.

Originally Posted by m4ubs

yeh but isnt he saying that he marked the datum line above the door frame coz all walls were meeting. He started tiling from some point below the line and all the fixed tiles are level...but when he measures from the datum line to the top of the fixed tiles in different places there is a 3mm discrepancy ? whats the point of the datum line ? i just dont get it.....im confused, lol
----
if he uses the datum line to measure downwards and fix tiles, then he might getting them kinda readings coz hes not holding the measuretape straight ? slightly unlevel n ur not gonna get a correct reading r u ? or am i still confused ?

I marked a datum line first. It finished bang on the start point. I put it there just as a guide.

I marked out a guage rod, checked obsructions for cuts with it etc etc. Marked lowest point to start, battened and started. On reaching each wall I batten level and continue constantly checking levels.

Use a steel 1m rule for more acurate measure than tape.

have the tiles slipped or are they all different sizes as this would through your line especially if using cross spacers.Is there ANY MOVEMENT IN THE WALLS?(GYPROC)

If you wanted to use a datum to ensure your grout lines meet up it does not have to be above the door just use your level to mark across the door frame at a more manageable height.

Originally Posted by tiler tom

If you wanted to use a datum to ensure your grout lines meet up it does not have to be above the door just use your level to mark across the door frame at a more manageable height.

Aha ... that's what I done this afternoon, I just made sure all was ok across the frame and put a few staff marks up it.
Just taking a little more care.

I love datum lines. I learnt them in aircraft engineering many years ago. If you put a datum line anywhere, you will ALWAYS get to your goal.

I put a datum line in the respected place for my tiling, place my battens, and it works out. You have to be careful when placing your lines on walls, as the plasterer, God bless them, always leaves a 'bow' or other thing in the wall. So, I find my level some times rocks on the wall, so , just take your time....sorted.