Fitting new joists to a stone wall using ledger plates

I sue this method because it is much simpler to fit the new joists at exactly the right height, once you have your ledger plates installed it’s very easy to fit the joists accurately.

Trying to concrete then in to holes in your stone wall is tricky, messy and may cause your joist ends to rot.

Drill 20mm holes to a depth of 40cm

Prepare 50cm threaded rods (14mm)

Use a resin anchor to fix the bolts in to the wall once you’ve vacuumed the dust out.

Use joist hangers to fit the new joists to the ledger plates


To keep foor joists at the same level you simply have to use a temporary brace across all joists which you remove after a week or two, once the mortar has set.

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Mmmm… been following with great interest…

The cellar joists and crossbeams are supported by treetrunks…in the part under my kitchen…:frowning: and the floor seems a little bouncy … now might be the right time to investigate…:wink: (another task on the long list… )

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Nicely done James, and just the job I need to start soon.

Can you say…

Did you drill the support beam first then spot through, or measure it out and with some clearance it aligned itself ?

What size bit did you use in the wall, and consequently what was the resin per hole usage, as it’s expensive stuff.

Did you have much run off when drilling the 400mm.

Did you actually need 14mm ?,as the ledger plate screws will sheer before the those bolts move.

Did you consider sitting the joists on the support beam instead of hanging them off it. Or maybe part ‘key’ them in ?

Did you need such substantial joists, I’m thinking 100x100 (same as elsewhere in my House).

Thanks for any answers/advice.


Hi @Tony_Marwood

I’ll get back to you in detail tomorrow, I’m a bit knackered from putting up gutters to be of any use right now!

I have your answers though!

A demain


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I drill (and countersink if you like) a hole at each end of the ledger plate and present it to the wall in exactly the right position, this is the awkward bit as you’ll need another pair of hands and some things to prop it up there with. Drill through these holes and in to the wall with your 500mm SDS bit.

Tape a smaller diameter piece of tube to a vacuum cleaner and clean them out. You can then squirt your poly resin through the timber and into the hole, you’ll use half a tube for each one. Slide in your threaded rod flush with the joist or you can cut any excess off later if necessary. Leave it to set. Place your washer on and hand tighten both. You can now drill the rest and repeat the process. Try to aim for the center of stones if you can see them.

The drill bit doesn’t run off due to the ledger plate keeping it aligned. You can use smaller diameter rod and a smaller bit I suppose but bear in mind that the entire weight of the joists, floor covering and whatever else will be above is going to rest on those rods.

You could sit the joists directly on the plates if you have the height to do that but then you’ll need to devise a plan to hold them in place, obviously the would just rest there but you could end up with a creaky floor if the move at all. This is why I use all of the nail holes in the hangers. Also you will need to hide the ledger plate in the plasterboard and dues to its thickness you’ll lose some space in the room. (I can expand on the if it’s not clear!)

I use the following table to determine joist dimensions. 100 x 100 is too small IMO.

Best of luck!

If you regularly do DIY, I highly recommend getting a copy of the book that table cam from, it’s invaluable.

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You can get the resin anchors and the rods quite cheaply at Screwfix

Many thanks for your response, I’ve asked someone who has access to download the relevant pages for me.

I most probably will sit my joists (whatever size they end up) on the Wall plate and Nog them to stop movement. I am covering a length of 12M which is equally spaced with two 10x8 Oak Lintels. One side has an end in tradional French Wall which looks like yours, but the other end is Concrete block. I do have a few spare old Oak Lintels, so might make up a two uprights and a cross lintel type arrangement for that end.

I may be back after I’ve consumed the info.


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Hello, I know this is a few years old now. But I wanted to say thank you for these instructions! We are renovating an apartment in Vieux Nice (our building is around 500 years old, give or take!). I’ve been wondering how to install a header plate in stone walls and this was perfect.

I do have some questions if you don’t mind answering: did you drill the 20 mm holes with a masonry drill bit? Or with a diamond core drill bit? If you did use a diamond core drill bit, did you do a wet or a dry drill?

How many drill bits did you go through?

And where did you find a drill bit long enough? I’ve found some 20 mm diamond core bits that are almost 40 cm but haven’t found a 20 mm masonry bit that long.


You need an SDS drill and bits - a bit like a masonry drill on steroids. If it’s a “one off” job, you can get a reasonable one for under €100. SDS drill bits are available in lengths up to 1m and up to 22mm diameter. You will only need one bit, and can use them dry.

Fantastic, thanks!

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Hello Rixa and welcome to the forum.

Sounds like you are in the middle of quite a project…

Please let us know how you get on… we can all learn from each other’s experiences… good and bad. :relaxed: :relaxed:

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Something like these should do it.


Dry SDS masonry bits, I just used one, the stone is pretty soft here.

Hello All, thank you James for starting this thread. I am busy fitting a new intermediate floor in what was an old stable and I’m using your method to fix the ledger plates to opposite walls which will support the joists.

I have one question though. What did you use to fill the uneven gaps left between the ledger and the stone wall? From the photos it looks like you used expanding foam, is this dense enough to tighten the ledger against or should i be looking at using something like mortar instead?

Thanks in advance for any advice you can offer.

Hi Pieter

If you anchor the rods in to the stone adequately you won’t need to fill the gap from a structural standpoint. It’s simply there for insulative purposes.

You’ll be able to adjust the plate evenly against the wall by tightening or loosening the nuts. Be sure to keep the face of the plate vertical or you’ll have trouble installing your joists. Essentially the whole floor is supported by the shear load on the rods. Once the joists are in place the plates have nowhere to move to as everything is then under compression.

Hi James, thank you for your quick reply!

I understand what you’re saying about not needing to fill the gaps behind the ledgers for structural purposes. However, I have already installed the ledgers and by using wedges and a laser have set them up perfectly parallel to each other (also ensuring that the faces are vertical). This has left a gap of up to 20mm in some places (I’m working with a rather rough stone wall!) and I can’t tighten all the nuts without the ledger bending in places. Hence my need to fill between the ledger and wall.

I have seen other people using mortar for this purpose but had hoped the expanding foam would work as it would be much easier to use!

If your plates are solid then I would foam it, alternatively you can use a ready mix mortar (sand and cement)

Good luck!