Hello Aidan, on the advice of my charpentier I fixed the ledger plates to the wall at 1 meter intervals. I wanted to hide all the hardware when the floor was complete so I drilled the holes in the ledger plates behind where each second joist would sit (joists are on 50 cm centres). I used 16mm threaded bar which I sunk 40 cm into the wall, to attach the plates to the wall. Also because I wanted hidden hardware, I used ledger strips to support the joists instead of joist hangars as James did in his project.
Do you have a photo of this, I have an area I’d also like to have hidden strips on?
Hi Martin, yes your barn would present a much bigger challenge than mine did! I was underestimating the size of the gaps I was dealing with but I don’t think I had anything over about 40mm to fill…
James seems to be the guru on this stuff, I’m sure he will jump in and offer some advice. Good luck!
Hi Tory, I’m away from home at the moment and don’t have access to my photos, but will do a drawing for you and try to post it here.
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Untitled.pdf (19.6 KB)
Hi Tory, here is a drawing of what I did. Concept was thanks to James and this design and lumber dimensions were given to me by my local Point P:
• Joists are on 500mm centers
• Ledger board bolts are on 1000mm centers
• Bolts were 16mm x 400mm
• Ledger strips were attached with 2 x 8mm screws hidden in the notch under each joist
The stabilizing boards were an afterthought which I thought would be more elegant than the Point P recommendation (the Point P design called for long screws to be screwed at an angle through the joists from the top and into the ledger board), and as the stabilizing boards would effectively hide the ledger board bolt heads, you could put the bolts anywhere you wanted to.
Also, Point P were basing their recomendations on 4m long joists using the standard pine beams that they sell. I ended up finding Douglas Fir beams elsewhere at a better price and according to my charpentier, I could have gone with 200 x 75mm beams instead of 220 x 75mm due to the Douglas Fir being stronger.
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Thanks Pieter,
Looks like a nice solution!
Hello there. Saw your contribution to the thread.
We are planning a ledger plate on the rear wall (and possibly the front) for our second floor joists.
The house is an old Granite built house in Haute Correze and the rear wall of the house is subterranean to around the height of the second floor joists. The old joists have rotted out in the rear wall and are all being replaced with Douglas Fir/Red Cedar joists which are 200mm x 80mm. Probably not helped by no guttering and cement render splashback covering the granite stone.
We plan to remove all the cement render and pointing and repalce with lime/sand. Oh and have fitted guttering!
Rather than reuse the old sockets (which are not evenly spaced) I want to use ledger plate and joist hangers.
Our walls are granite so I am concerned about drilling 40cm long holes. I do have a powerful Bosch Professional drill/perforator. What was your experience?
The ledger plate on the rear will be hidden behind a secondary inner wall so I am not worried about using galvanised joist hangers. For the front wall it is being coated on the inside with 11cm of hemp lime insulating render, then lime plaster. I have thought of a ledger plate for the front as well because the current joist sockets are not evenly spaced and will be lots of work to re-do!
Problem with this is that the galvanised hangers will be visible because they will stick out more than thickness of the hemp lime coating (11cm) - Ledger plate = 8cm plus galvanied hanger.
I really like your solution with a ledger strip and notches in the end of your joists. I presume the screws were 8mm diameter. Did you just have two behind each notched joist? How strong is this at supporting the joist compared to a hanger which has multiple screw fixings?
Is that the only support for the joist? Is the ledger strip just pine or oak?
Also you spaced the threaded bolts at 1 metre? Is this what was advised by Point P? In James original post his bolts look much closer together?
I would be interesting to hear your thought/experiences?
Hello Paul, sounds like a great project!
I can’t really comment on the granite question, I live on the Gers/Landes border and all the old houses around here are made of a very soft stone which I assume is a type of sandstone (my geology knowledge is pretty much non-existent!). James is the one with the real experience here and could probably offer some advice on that.
Everyone that I have spoken to is in agreement that removing cement rendering and replacing it with lime pointing can only be a good thing for your house (Not to mention taht it will probably look much better). I have the same problem with my house and I’m in the process of removing all the cement render and re-pointing with lime/sand.
Regarding the question of using ledger strips instead of joist hangars, I was somewhat dubious myself but after a lot of research, I have discovered that ledger strips are widely used worldwide and are considered to be equal in strength to joist hangars. I did use 2 x 8mm screws under each joist (PointP and my Charpentier laughed at me because they felt only one was needed) and I pre-drilled pilot holes through the ledger strip to ensure that it would not split. My ledger boards, ledger strips and joists are all Douglas Fir.
I was advised by PointP and my Charpentier to place the wall fixings at 1 meter intervals, which at the time I was happy with because it meant I could hide them behind the joists. PointP were basing their advice on a floor that could support 250kg/square meter. However, I added the spacing boards between the joists (which would cover the wall fixings) as an after thought and if I did it again, I would probably place the wall fixings closer together. My Charpentier just shook his head and walked away when I told him that, but hey, I like to over-engineer stuff!
My intermediate floor has been in use for nearly a year now (it is the base for a loft apartment - so normal load for a household application) and there has been no sign of cracking/sagging/movement of any kind. In my case the joist ends are visible in the rooms below because I used the bottom of the ledger plate as the fixing point for the top rail that supports the vertical studs which support the drywall. So the drywall does not extend above the bottom of the ledger strip. I’m very happy with the appearance as no fastenings are visible.
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Excellent information thank you. If I understand correctly you used the spacing boards between the joists to hide the bolt fixings. Does this mean you recessed the thread and bolts into the wall ledger plate itself?
I wont need to do this for the rear wall as a secondary wall will hide the wall plate, so I will just use joist hangers. For the front wall I think I will do as you have done. Did you fix the joists in any way or were they held in place by the spacer plates. How long were the 8mm screws you used? How far into the joist are they screwed? Seems mad to me that they take all that weight?
Also it seems like 1 metre spacing for the wall bolts is quite wide but it’s a lot less drilling, especially into granite? I have a twelve metre wall to do with three seperate wall plates. (front and rear) I was thinking I should buy stainless steel threaded rod not galvanised? Where did you source the resin? In James’ original post he used Screwfix own brand - Non Nonsense Resin Anchor. I can’t find this on the Screwfix France site? They don’t seem to have much compared to the UK site?
Hi James
I saw your great post/thread from a few years back about fixing a ledger plate to a stone wall using bolts and resin.
I just had a couple of questions. As the thread is old I didn’t know whether to contact directly?
Our renovation house in Correze is built into a granite hillside, so the ground floor at the rear is below ground level. All our joists need replacing as they have rotted out in the sockets in the rear wall. Rather than put new Douglas beams into the sockets I want to fill up the sockets with stone and lime/sand and then use a wall ledger plate like in your post. I am concerned a little about damp? The rear wall is currently pointed in cement with a splashback of cement about a metre up the wall. There was no guttering which we have remedied. All the cement render and pointing will be removed and redone with lime and sand so the wall can breathe so it can properly dry out.
Once the joists are fitted to the ledger plate with hangers we will be having a Porotherm (terracotta air bricks) secondary wall built in front of the rear granite wall on the ground floor level for insulation/moisture control purposes. It will have hemp lime applied on the inside face.
I have three oak joists which are 200mm x 80mm x 4 metres. I will need these to make three seperate ledger plates on a 12 metre back granite wall.
1.) For each joist/ledger plate what spacing do you recommend for the bolts? I was thinking one every 50cm or 60cm? The joists are being spaced with a 40cm gap between faces, so need to figure it out so they don’t clash with the bolts!
2.) Our stone is Granite so pretty hard. I have a Bosch professional SDS+ perforator/drill and some SDS drills which are about 450mm long. You said your stone was soft, but I have worries about drilling so many holes in granite, it’s very hard stuff! Any advice?
3.) I checked the link on where to buy the resin and threaded rods but Screwfix France have limited stuff compared to the UK site. Since Brexit the UK site won’t ship to France.
4.) Are the threaded rods galvanised or should I go for stainless, given the nature of the rear wall?
Any advice appreciated. Kind regards Paul
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In my case I placed the wall fixings behind the ends of the joists, but could have put them anywhere because I added the spacer plates as an afterthought. Either way, you will need to recess the nuts into the ledger board. IIRC a 30mm paddle bit cuts the right size hole to fit standard 16mm washer. The depth is determined by the thickness of the washer and nut, which I think was around 25mm. When I was finished tightening the nuts holding the ledger board, I went around with a mini-grinder and cutting disc and trimmed whatever length of the threaded stud was sticking out past the nut, ensuring the everything was flush with the face of the ledger board.
The joists are only held in place by the ledger strip from below, and located side to side by the spacer plates. Mine are not mechanically fastened to the ledger board. The screws that I used to attach the ledger strip to the ledger board were equal in length to the thickness of the ledger strip and ledger board combined.
I would check on the difference in shearing strength between SS and galvanised studs, I suspect that galvanised studs may be more resistant to shearing forces (price difference will also be sustantial). I bought the chemical anchor goo from PointP mainly because it was cheaper than anywhere else (I know, hard to believe, right?!) at about EU10 per cartridge, but it is sold by pretty much every Brico in France.
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Further to my reply above, don’t forget that the joists are pretty firmly attached to the ledger board by the screws holding down the floor that you put on top of them.
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Now that I think about it, I remember that James had used 14mm threaded rod for his wall fixings and I also had the impression that he placed them closer together than 1 meter. This was one of the reasons I went up a size and opted for 16mm threaded rod.
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james
Great advice thank you James, we have a Point P in Limoges so I will source the resin/rods there next time I’m over that way.
For your final answer, I actually have three oak joists that are 200mm x 80mm x 4 metres long. I planned to use these for the ledger plates. Would this negate the need for hardwood spacers?
Do you think I should treat the oak with a preservative or is that overkill? Also you think that stainless threads are overkill too?
I plan to remove all external cement render/pointing and redo with a sand and lime mix. This will help the wall dry out and breathe. The house is on extremely well drained soil and granite bedrock, it’s just been pointed and render with cement for decades (grrrr)!!
Don’t want those threads rusting out or the ledge plates rotting!
I would place the ledger bolts in between each joist at the same centers, so 400mm. If you want to kide them them countersink the ledger plate first with a forstner bit and cover them with the hangers.
SDS+ is all you need, just give it a break every few holes unless it’s a pro model
I don’t use Screwfix any more, just get it from Point P, it’s about 10 euros a tube, Fischer or their own brand is great. Make sure that you squeeze out the first part of the tube a bit until it’s mixing together or it won’t work. So waste a dollop at the start of each tube, then use the same nozzle for future tubes.
Galvanised rods will be fine
NB fit some bitumen of hardwood spacers to insulate from the wall if their is a risk of moisture transfer to the plate
And yourself, look out for white finger and tingling a sign to take a break. Nerve damage is permanent.
Use the best 4 point sds bits you can find they will outlast cheap ones 4:1 or better in granite.
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CORRECTION!!!
My apologies Paul, I was re-reading the posts above and realised I had given you dangerously incorrect information. I placed my wall fixings behind the end of each joist which puts them at 0.5m spacing not at 1.0m as I stated in my earlier post. Must be an age thing…
There is a lot of information on Google regarding ledger boards being used in the USA and the accepted practise there is to use half inch bolts spaced at 16 inches. This corresponds with James’ advice above to use 400mm spacing. Because I was wanting to hide the wall fixings behind my joists (and my joists are on 500mm center to center spacing) I decided to use larger threaded rod. Hence my decision to use 16mm rod.
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Thanks for the update!
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