How to shim lintels (process/materials etc)?

[g8dy]

Hi all, have been searching through internet for videos on how to shim a lintel and can't find anything. Would appreciate any advice on how to do this.

I'll be laying 1500mm long lintels in rows of 2 to span a total of 3000mm. 1800mm of the lintel will be on a concrete base and the remaining will be laid over paving stone. So there is about 10-50mm to fill from the wonky paving stones.

My plan:

Use steel shims (50mm x 50mm squares) at either end of each lintel and raise all the lintels to highest point as nessecary.

Next part im stuck on....what to do next? Lay a bed of mortar to fill the gap between the steel shim?
Do you also encase the steel shims in the mortar too or remove once the mortar has set?
Do you use mortar or something else?
Is there a limit to how high can you shim a lintel?
Will the steel rust, can you just use mild steel?

 

[Adam W.]

Slate, then point in.

As slate has been under immense pressure for 600,000,000 years or so, it is very difficult to compress it any more.

 

[g8dy]

Slate, then point in.

As slate has been under immense pressure for 600,000,000 years or so, it is very difficult to compress it any more.

ill see if i can find slate, steel seems like its much easier and cheaper to find though

Im a complete beginner to this, what does point in mean? Would you want to completely pack out the gap under the lintel?

 

[Adam W.]

You should be able to get slates easily enough and once you've built up the packing and it's carrying the load, just fill up all the gaps with mortar using a trowel.

 

[SLM]

Will the steel rust, can you just use mild steel?

The ph of the cement will passivate are the steel, and so rust will be inhibited. However, I’ve always used slate for this application.

 

[f114306]

I might be tempted to use a dry pack mix instead of mortar something like webercem grout which can applied in a variety of consistencies and has non shrink properties. Just used a bit with slate under a steel beam. Should be able to find it at your local friendly merchants.

CG

 

[g8dy]

Thankyou all for the info, ill see if I can get hold of some slate or steel shims and some non shrink grout.

 

[Phil Pascoe]

If you tell any builder you're putting in a lintel and need some non shrinking grout he laugh his socks off. See Adam's post above.

 

[g8dy]

If you tell any builder you're putting in a lintel and need some non shrinking grout he laugh his socks off. See Adam's post above.

Im clueless with all this haha, are you saying he'll be laughing because there's no such thing as non shrink grout?

Steel/Slate shims and mortar it is then

 

[Phil Pascoe]

No, just that ordinary mortar is fine. It's been done many millions of times.

 

[f114306]

Horses for courses, you pay your money and you make your choice. I chose the grout over mortar and probably like mortar users I’ve no cause to regret my decision. In building, woodworking and indeed life you’ll find that there are many ways to skin the same cat In the end the decision is yours. Members here will always give good advice based on their knowledge and experience doesn’t mean that you’ll get the same answer every time that’s the beauty of a collective.

 

[Bingy man]

Well to throw the cat amongst the pigeons plastic shims of various widths and as above a good mix of sand and cement. I use plastic shims / packers as the widths can easily be adjusted to get the lintel level and stable but agree with @f11 4306 that everyone has their preferred method and as long as you are comfortable with it and it works for you then stick with it ..

 

[g8dy]

Horses for courses, you pay your money and you make your choice. I chose the grout over mortar and probably like mortar users I’ve no cause to regret my decision. In building, woodworking and indeed life you’ll find that there are many ways to skin the same cat In the end the decision is yours. Members here will always give good advice based on their knowledge and experience doesn’t mean that you’ll get the same answer every time that’s the beauty of a collective.

Its relieving to hear this so thankyou. Its so confusing coming at this with zero experience, I'm slowly starting to understand that there are many correct ways to achieve the same result, and for something like a shed there's a little more leeway.

Well to throw the cat amongst the pigeons plastic shims of various widths and as above a good mix of sand and cement. I use plastic shims / packers as the widths can easily be adjusted to get the lintel level and stable but agree with @f11 4306 that everyone has their preferred method and as long as you are comfortable with it and it works for you then stick with it ..

Thanks for the tip, plastic shims are much cheaper than steel so I might go this route. Im guessing the mortar, once its set, is taking most of the loads right?

 

[Bingy man]

Its relieving to hear this so thankyou. Its so confusing coming at this with zero experience, I'm slowly starting to understand that there are many correct ways to achieve the same result, and for something like a shed there's a little more leeway.

Thanks for the tip, plastic shims are much cheaper than steel so I might go this route. Im guessing the mortar, once its set, is taking most of the loads right?

Yes absolutely, just make sure your push plenty of mortar ( cement ) under the entire length of the lintel and as far under as you can without disturbing its position. Don’t be tempted to lift or move the lintel to see if it’s stuck / adhered - just set it into its position level it up making sure it’s stable along it’s length and not rocking and point it up with mortar as above . Good luck and have fun

 

[Spectric]

I use plastic shims / packers as the widths can easily be adjusted to get the lintel level and stable

Slate will not compress but plastic spacers will.

 

[clogs]

just to add, I bought a an old place that used slate as a damp course over stone coffins for a foundation...
worked a treat....

 

[Bingy man]

Slate will not compress but plastic spacers will.

But the once the mortar sets it makes little difference, I’ve used slate many times but I find the combination of plastic shim sizes more accurate. I think both materials have their advantages .

 

[g8dy]

But the once the mortar sets it makes little difference, I’ve used slate many times but I find the combination of plastic shim sizes more accurate. I think both materials have their advantages .

This is what I was thinking too, the shims are just there to get the thing level, the full bed of mortar underneath does most of the heavy lifting

 

[Adam W.]

Try not to over think it, the best solution is the one that you have materials for. If you really want, you can use oak folding wedges.

It doesn't matter really.

 

[Bob008]

Hi all, have been searching through internet for videos on how to shim a lintel and can't find anything. Would appreciate any advice on how to do this.

I'll be laying 1500mm long lintels in rows of 2 to span a total of 3000mm. 1800mm of the lintel will be on a concrete base and the remaining will be laid over paving stone. So there is about 10-50mm to fill from the wonky paving stones.

My plan:

Use steel shims (50mm x 50mm squares) at either end of each lintel and raise all the lintels to highest point as nessecary.

Next part im stuck on....what to do next? Lay a bed of mortar to fill the gap between the steel shim?
Do you also encase the steel shims in the mortar too or remove once the mortar has set?
Do you use mortar or something else?
Is there a limit to how high can you shim a lintel?
Will the steel rust, can you just use mild steel?

Why do you need shims? Why can’t you just bed each end on a dryish

Hi all, have been searching through internet for videos on how to shim a lintel and can't find anything. Would appreciate any advice on how to do this.

I'll be laying 1500mm long lintels in rows of 2 to span a total of 3000mm. 1800mm of the lintel will be on a concrete base and the remaining will be laid over paving stone. So there is about 10-50mm to fill from the wonky paving stones.

My plan:

Use steel shims (50mm x 50mm squares) at either end of each lintel and raise all the lintels to highest point as nessecary.

Next part im stuck on....what to do next? Lay a bed of mortar to fill the gap between the steel shim?
Do you also encase the steel shims in the mortar too or remove once the mortar has set?
Do you use mortar or something else?
Is there a limit to how high can you shim a lintel?
Will the steel rust, can you just use mild steel?

why do you need shims ? Why can’t you just bed each end on mortar and level up ? Also 50mm is too small really you should be looking at something similar to the width of the lintel and 150mm long at each end
50mm is a very small point load and although you may be pushing in extra mortar it’s the shims that will be taking the pressure also it’s better to use sharp/concreting sand to bed on as builders sand shrinks