How To Reinforce Floor Joists / Beams

[@DerekTJ]

This is very good for me as I've just had a rewire and new heating system put in our '49 semi in Dublin. I was cringing and the amount of holes drilled into the joist by both trades. I'll use this method for repair. Many thanks

[@PaintingandDecorating]

Thank you.. easy and robust.

[@johnriff85]

You're a good man. I'm dealing with a similar situation but with 3" PVC passing through the 2x8 joists, which is what led me here. I know how to sister a joist, but this is also a great way to add strength to an already sistered joist as well without making the supports too thick for plumbing and electrical. Sending love from the U.S.A.!

[@PaintingandDecorating]

Thank you.. your welcome.

[@MOAB-UT]

Iron and/or add a floor support underneath.

[@tonystone5548]

Without getting into technical details such as explaining all about the second moment of area and the properties of marine ply, you’ve designed, demonstrated and constructed a proper engineering solution to a problem. My senses tell me that your background is not painting and decorating. Credit to you

[@PaintingandDecorating]

My dads was a painter and decorator.. but I've also been around building work and love solving problems.. always a solution. Thanks

[@DD-it1th]

Perfect. I’m currently in the process of moving my bath into the centre of the bathroom and need to strengthen the joists there. This is excellent.

[@PaintingandDecorating]

Thank you.

[@barringtonsmythe3464]

How many times have home owners not done this. Insightful. Thank you 👍

[@neilshearer7513]

Thanks for sharing this technique. It's just what i need for strengthening the floor in a bedroom to bathroom conve😊rsion. Really well explained too 👍

[@PaintingandDecorating]

Thanks you're welcome. 👍

[@MarcusT86]

Thank you so much for this video. I have my upstairs walls built on top of floorboards too. I'm replacing all the upstairs flooring, but was worried about cutting the floorboards back to the nearest joist after the wall. Glad to see you did it and the wall is holding up solid! Now I feel more confident doing it.

[@PaintingandDecorating]

Thank you.. yes not easy to get your head round when it's in such a mess. And built so things don't come apart easily.

[@danielcumisky7259]

With the wall being built ontop of the floorboard which is presumably nailed into the joist under the wall how do you get the small sections under the wall out and fit new boards afterwards.

[@mstao63]

Really informative. Well done.

[@clairescott8902]

Brilliant... you just made a problem very approachable. Thanks.

[@PaintingandDecorating]

Thanks

[@bluecobra6294]

Amazing method, insane strength, super video many thanks

[@Christopher_T_Paul]

Plumbers are the worst for doing this. I've seen many cases where a plumber has hacked out half a joist to run waste pipes and often this will run the extent of the bathroom, over several joists. I think the worst I have seen is a 110mm soil pipe running through a joist that also had a hole directly underneath for electrical cables, there was probably only 2" of material left to support the floor.

[@edwarddoyle9231]

Hi, nice video - We had a similar problem with sagging rafters on a 200+ year old farm house in the west of Ireland when re-roofing - the underside of the roof was t&g match board that we wanted to save - We were lost as to do next - i phoned an architect friend told him my problem, He explained that I should strap the rafters on one side with 25mm X 160mm timber screwed with 65mm #10 hex head smooth shank coach screws , glued with polyurethane gap filling glue, Using glue was a bit messy , but what a wonderful job. On our way back home to London we bought a case of wine for the architect. Ed,

[@PaintingandDecorating]

Thanks.. great that you could save it..

[@SteS]

Good to see something different. I would've staggered where the ply was joined but I'm sure that's fine. I done the same recently and used M12 nuts and bolts every 400mm, large penny washers and dog tooth connectors. But as long as your engineer's happy. I was sistering joists for an attic ope and that's what an engineer I asked spec'd.

[@PaintingandDecorating]

Thank you.... the glue is stronger than wood so once cured its better than just bolts or screws.

[@jsj381]

@@PaintingandDecorating I thought you did only Decorating? Jack of all trades good job man👍

[@PaintingandDecorating]

@@jsj381 Thanks.... yes can turn my hand to a lot.

[@SME_Ste]

Ideal adhesive for this is PU wood adhesive, that’ll fill any small gaps or deviations in the joists. M10 coach bolts at 300 centres in a diamond formation, solid as a rock!.

[@PaintingandDecorating]

yes a few ways it can be done different adhesives.

[@MOAB-UT]

Leave a gap near the wall. Sand down or use something to prevent rubbing of those wires. It's too tight- things will move. You should jack up from underneath so it is dead level first. Use of metal/iron would be superior...but I am sure this will hold well. Much better then it was anyway.

[@youtoob1811]

Seems odd that the joists would need strengthening given how close the bath will be to the wall (where the joist will be strongest). If the bath was going closer to the middle of the house or faced perpendicular to the wall it would make more sense. Either way, nice work.

[@PaintingandDecorating]

Thank you..

[@MarcGray1990]

Well we’ve had the brother act in previous videos, and now we’ve got the joist “sister act” ! See what I did there? My jokes are terrible 😂😂 well explained and good job well done! I’m sure you will end up decorating the new bathroom! Would be good to see it finished!

[@PaintingandDecorating]

Thank you.. lol. yes got the painting job... ceiling, door and casing.

[@MarcGray1990]

@@PaintingandDecorating top man!

[@robinford4037]

If you did this more often I would use a notched trowel/spatula (plastic maybe) to get a better coverage of glue, but also to stop wasting time on trying to find a brush to sacrifice, I've always regretted using up a brush needlessly, about 2 hours later on another job. Also a 10.8v (12v) drill (for quite 😀) or impact (if you want to end up deaf or hate the neighbourhood 😡) not only for tight spaces but for when you drop it on the lathe and plaster (about 10 seconds before the end of the job)

[@siddall78]

Definitely waiting for the expanding foam to come out😂 good job though, thought you would of staggered the joints, but i suppose when set it will be solid

[@PaintingandDecorating]

Thank you... the glue used is actually stronger than the wood.. once dry fully the wood will splinter first than the glue giving up...

[@JulianFoster-og8ru]

Interesting to see, although from an engineering perspective your first ply panel is upside down. Reinforcement is most effective across the bottom of a beam carrying weight from above so your solution would be even stronger if you flipped the first panel and added the ‘horseshoe’ part to the top not the bottom. Been a long time since I’ve done the maths but sure that’s correct. Happy to be corrected though! Thanks for sharing.

[@PaintingandDecorating]

@@JulianFoster-og8ru yep.... although how I get it under the wires would be very difficult. Also I thought the cut on top would open easily with pressure from being forced down. Once the wood is glued it won't break the glue is stronger than the wood.

[@JulianFoster-og8ru]

@@PaintingandDecorating good of you to reply, thanks. Weight on the beam will force it into a smile not a rainbow- so the notch cut on top would try to close not open, filling that gap with the piece removed would stop that happening and restore most of the strength of the ply. With the notch taken from the bottom, that will try to open and eventually split the ply as weight is put on top of the beam. Anyway I’m sure your reinforcement with screws and glue will work just fine. All the best.

[@johnwealthy6044]

Fantastic video many thanks. I have decent enough joists and no loads as it is on the landing. Only thing is, some notches are a bit wide where the plumbing is so need to put some strength back. (TBH, it has been like this for 30 years so sure it is OK but I feel I want to do exactly what you have done here just to be sure)

[@PaintingandDecorating]

Thank you. It will help in less movement in the floorboards.

[@johnwealthy6044]

@@PaintingandDecorating Is it essential to do both side of the joist for the strength to be improved?

[@TheHeavyend81]

Time consuming but definately a great job.

[@richardweinberger2756]

I was curious when he said he was going to reinforce the beam with "quarter-inch" plywood, but it was really three-quarter inch. I do really enjoy watching your videos.

[@PaintingandDecorating]

Thanks

[@huejanus5505]

Would it have been better to slip the plywood under the wires with the cut out on top of the wires instead of below them? That way the plywood is continuous at the weakest part of the joist, the bottom. It would be easier to reinforce the cut out over the wires than under them as well.

[@Pseudify]

I think it might be slightly stronger the way he did it. The glued parts of that strap are stronger than the unglued surrounding plywood. Using your method there is no glued plywood on the bottom. But I suspect the engineer would have approved it either way. Btw, I’m not an engineer.

[@Mike-su8si]

Nice stuff I've done the same just without the Elmer's glue

[@ratchriat1716]

that's a good fixe for many years to come.

[@PaintingandDecorating]

Thank you.

[@paulcrawford50]

A job well done.

[@PaintingandDecorating]

Thank you.

[@tonyp9601]

Very nice.

[@PaintingandDecorating]

Thank you.

[@iwo2024]

Can this method be appied to straighten sagging floor joists (using acrow props from below) as well as to add strength to the joist?

[@PaintingandDecorating]

If you slowly jack the sagging joist back then use acrow props to hold. You can strengthen the joist then. Thanks

[@markrowland5393]

Very interesting. Thank you.

[@PaintingandDecorating]

Thank you.

[@miker8149]

Great informative vid, cheers

[@PaintingandDecorating]

Thank you.

[@alanbroderick1283]

Great! I can notch my toilet pipe accross my 6" joists and get rid of the boxing

[@kingofthetrowel1725]

Nice one 👍 that’s never gunna move is it 🙌🏻🙌🏻 did you say you had to have it inspected by building control inspector, I would imagine they would be over moon with that mate , I’ll be doing same when it comes to doing mine, nice one mate 👍👍

[@PaintingandDecorating]

Thank you. It got passed by the inspector..

[@QueenAstroParticle]

Thanks for sharing this video. Sorry to be off topic, but is the dog ok?

[@carle5538]

I guess this would be a second way of handling the problem, other than putting a beam next to the cracked one and sistering it with nails.

[@alvinosullivan2804]

Nice job!

[@PaintingandDecorating]

Thank you.

[@davidvanweeghel8194]

Great video! Could this also be done with OSB 3?

[@PaintingandDecorating]

@@davidvanweeghel8194 no only wood glue.

[@nickrider815]

I don't understand why that joist needed reinforcement. That's one seriously chunky 3" or 4" beam. When you consider the 47mm x150mm pine twigs new builds are made from today it looks like overkill to me. What was the bath? A victorian cast iron freestanding tub?!

[@Tom_Prendiville]

Not just a pretty face aye 🤣. Its snowing again here in Durham 😊

[@PaintingandDecorating]

Thank you.. lol.. we had snow now rain.

[@boulengerochromis]

Any reason why you wouldn't use 2x10s or angled iron bracing? I love the attention and care, but plywood won't do much

[@PaintingandDecorating]

Check out how strong engenered wood is.. easy to work with and last a lot longer than iron.

[@justintemp]

After the diluted pva I was waiting for the expanding foam to come out... 😂 Did you find the boards were fit even and level? Didn't have to cut any off at top?

[@PaintingandDecorating]

Thanks and no kept them at the right level.

[@justintemp]

@@PaintingandDecorating makes it easier when you don't have to cut the tops.

[@johnnicholson9118]

your a painter & decorator ? ive never met a brother of the brush who would take this job on .when you started coating up the joists with a distemper flat ./ large emulsion brush .that was enough for me .

[@Astratov7]

Do you think, that system could be used for strength the loft beams for loft conversion? It would be much cheaper and easier.

[@PaintingandDecorating]

no.. they are ceiling joists not floor joist.

[@BsECowley]

Great video. Do you think this would also be suitable to resolve bouncy joist issues?

[@plummetplum]

Yes.

[@bazzbazza2786]

Thanks for sharing your video, I found it very interesting. Could I go ahead and strengthen my loft joists this way (2x5 spaced at 16 inches apart), to create a strong floor?

[@PaintingandDecorating]

Thank you and no your joists need to be the correct size for holding a floor. This would strengthen what's there but not enough for the over all weight. Floor joist and needed

[@bazzbazza2786]

@@PaintingandDecorating Thanks 👍

[@garvielloken3929]

Nooice!

[@Solidsnake0208]

Surely you’d be better off adding a few noggins to spread the load across the whole floor?

[@victorvek5227]

Never have I ever seen anyone strengthen a floor joist with glue, screws and plywood.

[@PaintingandDecorating]

Works really good.. engineered wood is stronger than normal wood.

[@megaman2016]

I was thinking the same thing, doesn't look legit

[@PaintingandDecorating]

@@megaman2016 totally legit and passed by the council... Happy days...

[@PaintingandDecorating]

@@ianhuds2206 Engineered wood is designed to be stronger than normal wood. Thanks

[@robertbeal]

Hmm isn't half of the plywood layers, the grain is facing downwards so is weaker. I'd expect timber with all the grain facing along the joint to be much stronger.

[@justintemp]

Great video. How long it it take in total and did they put plank floorboards back or large sheets of floorboard?

[@PaintingandDecorating]

only took 2 days and the plumbing has not been done yet.. thanks

[@arf4n166]

Can you use normal 18mm ply? Such as hardwood ply

[@PaintingandDecorating]

3/4 inch yes

[@nickevans7049]

no need for this lol keeps him in a job i suppose !

[@TomTomTomTom538]

If that's what the engineer has asked for and what the building inspector is looking for then it would be foolhardy to forego it and then have to rip out a freshly installed bathroom to do it anyway. Makes sense to get it done now while the rooms empty even just for peace of mind

[@tomoore1970]

Having the wires below the cut ruins the integrity of the sister. Had you put the cut on top the bottom would stay in tension.

[@ranat5526]

How are your knee's?

[@PaintingandDecorating]

Had my knee pads on but they kept slipping.

[@ericthekingthekingtheking4842]

Where you based pal i could do with a good all rounder

[@PaintingandDecorating]

Sorry no details

[@ericthekingthekingtheking4842]

@@PaintingandDecorating What

[@PaintingandDecorating]

@@ericthekingthekingtheking4842 L just showing some of my work but not looking for work.. sorry

[@ericthekingthekingtheking4842]

@@PaintingandDecorating Oh right ok no problem

[@edzanjero353]

Wish I understood low volume British? Irish? Scot?

[@moeenahmed6853]

Is wood glue a mandatory to put on? Can you use it with out instead??😐 Was this asked by the structural engineer?

[@PaintingandDecorating]

Glue is very important it bonds the wood together... screws are holding till Glue dries and has full strength..thanks

[@TheNorthernmunky]

Not a good fix the beams would only be as strong as the thinnest part of the ply, this will not stop it flexing especially as you’ve patched in several pieces of ply in the middle run of a joist. The whole point of sistering is you put the same size joist in next to the existing joist so it splits the load

[@PaintingandDecorating]

Ply wood engineered wood for super strength. Wood glue is stronger than the wood itself. All work was passed for safety so the build could continue. 👍

[@adamsala9291]

Stick with painting one trade!

[@FiftySixish]

There is a lot wrong with this, it doesn't act at all how you think it does. I'm actually thinking that this video is satire as you mention repeatedly how unbelievably strong it is at the end of the video. First, if the ply doesn't span the entire distance as a continuous member then it won't act as one. This means the entire thing is redundant apart from the local strengthening around the notches. This is equivalent of putting stickers on the side and claiming it is strengthened. The local strengthening around the notches also has a very low strength due to; the weak and brittle material used, the non-structural adhesive, and, the small cross sectional depth resisting the bending at the notch location. No professional would put their indemnity insurance on a detail like this. If this collapses and someone is in that bath, you'll be responsible. Contact the homeowner ASAP!

[@PaintingandDecorating]

It is perfectly fine and got passed by council standards. Thanks

[@beetleclemens3727]

Very boring work