How thick can a starter mortar course be as a difference in foundation level.

[simhya]

Hi All,

We have had our foundations piled and poured. The concrete height however is around 40mm difference in height from the highest point to the lowest point. is it ok for the starter mortar layer to range from the standard 10mm thick to up to 50mm thick over quite large runs.

I know our pilers are shocking but we are where we are, so just looking for practical solutions now.

We also needed to get to 715mm from the top of the highest point of the foundation level (remember the lowest point is 40mm lower than this).

Our levelling up solution to get to 715mm high from the highest point is...(using different thicknesses of bricks to make it work).....

Bottom → Top (with levels)​

1. Bottom mortar – 10 mm. → Level: 10 mm
2. Trench block – 140 mm. → Level: 150 mm
3. Mortar – 9 mm. → Level: 159 mm
4. Crest red brick – 80 mm. → Level: 239 mm
5. Mortar – 9 mm. → Level: 248 mm
6. Crest red brick – 80 mm. → Level: 328 mm
7. Mortar – 9 mm. → Level: 337 mm
8. Crest red brick – 80 mm. → Level: 417 mm
9. Mortar – 9 mm. → Level: 426 mm
10. Crest red brick – 65 mm → Level: 491 mm
11. Mortar – 9 mm. → Level: 500 mm
12. Thermalite – 215mm → Final level: 715 mm

or we could use the following.....

All levels from foundation:

1. Bottom mortar 10 → 10 mm
2. Thermalite (215) → 225 mm
3. Bed joint 9 → 234 mm
4. Red brick (80mm) → 314 mm
5. Bed joint 9 → 323 mm
6. Red Brick (80mm) → 403 mm
7. Bed joint 9 → 412 mm
8. Red Brick (80mm) → 492 mm
9. Bed joint 8 → 500 mm
10. Thermalite (215mm) → 715 mm

Can I ask the brickie to grade in the 40mm difference in height of foundation which would make each mortar line thicker to around 15mm thick for the first option or 17mm thick for the second option (less courses).

As you can see, I can use various bricks to get to the right height from our highest point, but just worried about using a 50mm thick mortar bed at the start to get the base layer level so trying to find solutions to grade it out.

Any suggestions or are we ok to make alot of the starter course 50mm thick? would it be possible for a brickie to lose 40mm difference in foundation levels across this many courses?

 

[jj4091]

Not a brickie but would think they would make it up slightly in each course as the wall was rising. As long as they are made aware of the problem.