How to Flash Joints in James Hardie Siding

[@markbither]

You have good ideas, but there are definitely manufacturers recommended installation instructions and tools that will make your job easier. A few products our crew use...Bear skin flashing strips, (cheap and quick, no extra fasteners/penetrations needed). Gecko exposure gauges, and a good coil nailer with a lap siding gauge attached to the tip. As a few people have mentioned, warranty is voided if joints are caulked, not sure about the power grab, (good idea, but imo not necessary). Other than that you're on the right track, thanks for the share.

[@businessconstruct]

Raw aluminum flashing or any other product that may bleed or adversely react with cement products. Painted or coated aluminum flashing is recommended.

[@rich.trails]

James Hardie now recommends just the flashing, a light touch butt connection and no caulk.

[@steffanpaleski9457]

For those who are curios you should be using at least 1 3/4 coil nails. also you should be using a dark color, coated flashing. lastly you should never caulk butt joints. The reason for the dark coated flashing is houses flex and a darker color will look as a shadow and be unable to see easily. Butt joints should be moderately tight, hardie doesn't shrink or expand so the joint will stay tight. Never caulk your butt joints, as the HOUSE expands it will push the caulking out or up causing asthetic problems as well as pushing the siding. Hardie recommends a 6" gap from the ground, 1-2" from decks, roofs, patios, and 1/8" from windows and doors. windows and doors can be caulked with 100% latex acrylic Hardie rated caulking. Always nail 1-1 1/4" down from the top of the board and 1/4" from ends :)

[@steffanpaleski9457]

Also cut with power shears to eliminate the dust saws will produce

[@JamesGlassJamesGlass]

Good question! The correct hardware is extremely important and James Hardie lists exactly what to use on the instruction sheet. I was using hot dipped galvanized rink shank nails, but you can also use stainless (which is total overkill). Never use anything less than hot dipped galvanized. Spiral shank is acceptable also, but ring shank is superior.

[@roberttitus3406]

7"×3" rooting paper works excellent. Heck of alot cheaper than tin flashing

[@JamesGlassJamesGlass]

In certain areas of the country (not ours) a rain screen is absolutely necessary. Also, areas with a lot of driving rains, both a rain screen and furring strips is a must. When furring the siding off the rain barrier, it is important to make sure both the top and bottom are vented so there is excellent air flow and drainage behind the siding--and don't forget the bug screen!

[@bmac65]

Great video. Extremely informative. I now have a clear understanding on how to flash joints, however I have a couple questions I wanted to run by you and get your input. My construction is felt board siding topped with a foam insulation and then a water barrier. I currently have vinyl siding on the home however due issues to Complicated to discuss on this form I'm interesting in replacing with Hardie lap siding.

[@GumbootZone]

The old instructions, for unpainted Hardie, said what is shown here, but without the flashing. You leave a small gap (about coin thickness) to hold some caulking, then it all gets painted over. The caulk seals the joint, although it's still good to flash for a backup like you did. The new instructions, specifically for pre-painted Hardie, says use flashing, don't caulk, and place joints touching. Both types of Hardie say leave gap at corner/window trim, which does get caulked. I had a friend who did his own house with pre painted Colour Plus and mixed all the instructions together. He flashed his joints, left a gap a full 1/8th, and didn't caulk. Up close his house is full of black, vertical lines where all the butt-joints are.

[@JamesGlassJamesGlass]

+Kauwhaka Yes, exactly. I'm not sure why people can't differentiate between unpainted and pre-painted Hardie. No caulk with pre-painted and caulk for unpainted.

[@Hernandez_O]

How come you didn’t mark the studs on the wall? Are you randomly nailing hoping it strikes a stud? Every nail has to have a stud behind

[@kennelson5096]

Aluminim will oxidize when placed against cement. Flashing a good idea, but not with aluminum. I use 30# roofing felt.

[@bmkurtz3]

Do you use power grab along the entire end of the board/siding when installing or just the ends?

[@JamesGlassJamesGlass]

I use power grab along a minority of the bottom. Remember, if water does get behind the siding, it needs to drain out underneath, so if you line the entire bottom with powergrab, it will form a water proof barrier and that's a bad tihng! A few dabs will do ya!

[@JamesGlassJamesGlass]

Haha. I will check it out. It might take a few days--we just added a new baby boy to the mix today! I'm being used as a sleeper sofa right now since new baby Eli spends most of his day sleeping on daddy when not nursing!

[@fredsmith8957]

All this is good if you live in an area where you never have high winds. Hidden nails are cute until your siding starts to "wave" in wind and loosens nails. Same that happens to slate roofs. It works on down weight until gusts loosen your nails. Better think about hand nailing bottom with screw shank nails and set them. Caulking is mandatory!!

[@ayrianjorgensen5446]

Question. If the siding is already installed without flashing, can flashing be installed at the butt joints without removing the siding?

[@shawnyork2083]

yes

[@roberttitus3406]

Yes just remove a few nails

[@ivanmceachin5234]

I live in the Dallas TX area and I notice that the majority of the new homes being built that use Hardieplank, have a small half moon strip that covers the seams when 2 boards butt up to each other. If you look at the underside of the board, the two planks actually fit into a groove on both sides of the strip. It appears to eliminate the need for caulking and is very attractive. The problem is that I cannot find anyone that know who supplied this strip for covering seams. Has anyone else seen this technique used?

[@JamesGlassJamesGlass]

It's not required here, but I do it sometimes. I use 3/4" furring strips between the Tyvec or rain screen and then secure the siding to the furring strips. In coastal areas, this is mandatory. In the dry desert out west, it's overkill.

[@bmac65]

this provide a 3/8 inch build off from the structure to mating surface of the hardy plank. Thus air induction permits moisture evaporation. Have you seen this practice in your area, and do you recommend?

[@kookiethebear]

For anyone watch this nearly 10-years after posted... DO NOT use caulk! DO NOT use a framing nail gun, use a roofing nail gun (round magazine).

[@chipisbell7075]

Hardie is pretty clear about not using caulk. They suggest as close to a color match as possible for flashing.

[@roby3291]

For anyone watching this 3 years later, DO NOT use a roofing nail gun. Use a siding nail gun.

[@bmac65]

I thought I read in a technical journal articles from James Hardy that you no longer need to calk butt joints if flashing and rain screen are implemented is this correct and have you seen this? Do you think this is a good approach?

[@bmac65]

I live in the Midwest specifically Indiana I've seen a lot of documentation and information on the Internet about rain screens /rain guards. It appears that if you apply hardie board directly to the vapor barrier a short time afterwards the paint will begin to fail due to posture buildup. Apparently Hardy recommends rain screen

[@bgt63]

You can Get small pieces of joint flashing the same colour as the siding when you order. field joint caulking looks rough compared to two factory ends butted with flashing.

[@roberttitus3406]

I like to nail 1/8 to1/4" from bottom lip as to just miss the lap

[@markdeezy1]

your not suppose to caulk the joints. Just but factory ends and flash cards. never caulk and paint them

[@bessiefunk2037]

Through all the mish mash of comments, what correct flashing can I buy at a big box store that will not disintegrate. Also, would you put flashing behind an end that butts against a window frame?

[@JamesGlassJamesGlass]

+Bessie Funk Coated aluminum roll flashing.

[@taron.y]

Coil stock, color to match the siding...cut on the site...

[@johnwallace2764]

hey james i have a client who wants 4x8 sheets of hardie siding installed, he wants to use h trim and z trim but ive never seen it done like that before. what fasteners do you use if you install 4x8 sheets with h trim and z trim?

[@John-ih7gp]

John Wallace screws are good for this. are their battons going up? I've seen many people use stainless screws. expensive, but aesthetically pleasing.

[@johnwallace2764]

John Allan no there are no battens going up. thats why im not sure what to put over the screws to hide them

[@gregtpa1]

Fair enough. I am curious to see what you think and welcome your thoughts.

[@lorettapowers5013]

What type of nails are you using in your framing nailer?

[@alexanderdeclercq982]

My house has been resided with hardi-board after a hail storm destroyed the vinyl siding before i bought it in southern Alberta, it was a rush job and someone didn't know what they were doing because there are recessed nail holes in the middle of a lot of the boards. Now I am in the middle of filling & painting them all. Sigh, oh well, I will get err done.

[@JustaManSelling]

Actually James Hardie Corp. Recommends galvanized steel, NOT raw aluminum. Always best practice to refer to the manufacturer's specifications and installation instructions. :-)

[@iamaGod357]

How do I flash asbestos siding?

[@bty1471]

Air Handler same way

[@heinpkoi]

should you be using some Gecko to save time during the installation instead of a 6" level ?

[@JamesGlassJamesGlass]

Serge Desrosiers The Gecko is a nice siding gauge--I use that too.

[@MrTHEBRITINWA]

Typically Hardi Siding is not caulked in the field…….

[@deztub4704]

I hope you painted that that cut joint what I see by that flashing

[@truckinforever985]

Did you use staples for your house wrap

[@JamesGlassJamesGlass]

Cap nails, sparingly. Staples often leak.

[@JamesGlassJamesGlass]

Although I should add: I'll get top secured with slap staples but I use tyvec tape over those few staples.

[@peterdittler7068]

Would have liked to see how to flash under window sills. Also will aluminum flashing chemically interact with cementatious products? Otherwise a very informative.

[@SamSung33377]

Use galvanized flashing

[@9mmsteve]

Oct 2008 James Hardi says DO NOT caulk joints, just flash. Why are you still caulking them.

[@JamesGlassJamesGlass]

n4ktz Only for color plus siding--which this is not. See James Hardie PDF dated September 2013. jameshardie (dot) com/d2w/installation/hardieplank-hz5-us-en.pdf

[@9mmsteve]

No, I spike to James Hardi and BOTH ways are acceptable. Either flash each joint and but them up right against each other OR no flashing, leave just a small space between joints and caulk. The preference of flashing over caulking is much LESS maintenance.

[@JamesGlassJamesGlass]

See the service bulletin at the above link. If u have a link from her did that contradicts that, please share here. Tx.

[@DukeLaCrosse20]

I see this which says not to caulk neither the vertical joint, nor the horizontal overlaps... www.jameshardie.com/d2w/technical-bulletins/9-joint-flashing.pdf

[@ellenfuller4393]

what about the hardi board that's not made of the cement

[@rickstout01]

There is no such thing. Hardie board is a cement based product.

[@JamesGlassJamesGlass]

Hardies recommends a rink shanked hardware, so no on the roofing nails (you can google their pdf on install) At a minimum you want to flash like this video, but if you live in areas of driving rain, then you can buy really nice flashing kits and I'd suggest furring strips between the air-barrier (Tyvec) and siding. This air barrier is vented top and bottom, but also let's condensate or water to drain out. You need a mesh screen to keep insects out.

[@christaylor2574]

Thx for the explanation of importance on flashing butt joints. It may to ur advantage before making future videos to check some other videos on the importance of using a A-frame ladder and how to correctly set one up before using!

[@JamesGlassJamesGlass]

To be clear: you have masonite (the press board stuff) then some foam, then some vinyl? It would need to all come off to the orginial sheating, install new insulation and air barrier (poly iso as thick as you can afford and Tyvec or equiv.) and then install the James Hardie. You're might be looking at new trim also. At this point there's no way you could continue to build out with a third siding!

[@reciprocait17]

could i tape behind the butt joints with silver ducting tape?

[@JamesGlassJamesGlass]

That wouldn't stand up to the elements. The duct tape is an interior product also. I'd say the method in the video is the least amount of flashing one would want and in coastal areas or high wind areas, then the siding should be set out from the sheating with 3/4 firring strips.

[@angelsmultiserviceinc1972]

Why you install 2 small pieces there when you can install one long piece

[@misterlyle.]

To reduce waste, but mainly in a place where it will not be noticeable.

[@huejanus5505]

I put this kind of flashing on every joint. As well, i put caulking on the edge of the boards to be butted together. I figure it’s cheap insurance.

[@MrMixmasterslick]

Clipped head framing nailer? Torpedo level?

[@JamesGlassJamesGlass]

Full head, torpedo level, 6' level, and laser level back up every few course of siding. Clipped heads are a bad idea for both siding and framing. Our state doesn't allow them for framing (which is good) and though they would be allowed for siding, the risk of pull through would be too great for the incidental cost savings. The hardware I used is Hardie approved (hot dipped galvanized or stainless) and in most cases hot dipped galvanized since the hardware is covered by the subsequent course. In the event I have to have exposed hardware in a rain driven location, then I'll used stainless. I'll also use the Hardie jig to nail the next course, but I'll still double check level with laser and levels. The snapshot of this video is the importance of flashing seams.

[@GumbootZone]

+James Glass I have the same type of nail gun and although it has an excellent depth adjuster, I thought it would be to powerful for Hardie board. You haven't had trouble with it breaking off chunks?

[@JamesGlassJamesGlass]

+Kauwhaka I would use full head nails (not clipped head) and then dial in the gun so you don't bust the Hardie. I've never had a problem. Also, I used Hardie approved hardware--it needs to be stainless or hot dipped galvanized.

[@shaunadrackett6787]

Since Hardie is now saying not to caulk the butt joints, could you just paint the flashing with touch paint? Also, what color planks are those? Very nice. Heathered Moss? Thanks

[@JamesGlassJamesGlass]

Hey Shauna! I think there's some confusion here between regular old Hardie siding and the fancy ColorPlus siding. This is just regular old siding, so it must be painted (within 180 days of install) and the pdf allows for caulk in the butt joint, but on the Color Plus stuff, you are correct, Hardie suggests no caulk. I think you think this is ColorPlus (hence the question about which color this siding is), but it's just regular old siding that must be painted. Although, it is quitely a nice color unpainted! Here's the pdf found at Hardies' website pdf/technical-bulletins/9-joint-flashing.pdf

[@bgt63]

BTW you should also mention that field joints should be factory ends with the cut ends at the corner. makes a neater installation.

[@rickstout01]

You don't always have that option unless you use a full piece. Can't flip the newer Hardie top to bottom because the bottom edge is angled.

[@bgt63]

+Don Netto you will have pieces you can cut from the other end

[@adamhutchins1791]

3" pice of flashing at laps the lap is 1" we flash 3/4

[@squadman33]

Right idea, but way too big flashing piece. Thanks

[@jessespad]

I saw this and I was like, "whoa, my metal was too thin!"

[@jmjolnir]

It specifically says do not caulk butt joints in the field only at the ends

[@JamesGlassJamesGlass]

You're right.

[@rickstout01]

Don't think using power grab on the bottom edge is part of the recommendations on the Hardie site. Interesting idea though.

[@gregtpa1]

I agree that the butt-joint must be flashed to prevent water intrusion. It is not "if" the caulk is compromised, but "when" it is compromised. And, Hardie does not recommend caulking the butt-joint on the color-plus siding! If you're going to use a butt-joint flashing, why not use the one that actually works:The ProLine Plank Flashing from Tamlyn. You can watch the video by searching: ProLine Plank Flashing

[@qmax-en5ry]

you are using aluminum flashing, that's wrong, when aluminum gets in contact with concrete(hardie plank )it will corrode the aluminum

[@JamesGlassJamesGlass]

+qmax1969 On page 15 of the James Hardie best practices guide is does state "James Hardie does not recommend the use of mill finished, raw aluminum flashing or any other product that may bleed or adversely react with cement products. Painted or coated aluminum flashings are recommended." You're not wrong, at least as Hardie's materials state. Where we live, I've experimented with standard flashing and haven't any any issues with either corrosion or bleeding. I can't see why corrosion would even occur because there's nothing in the siding that would cause a galvanic reaction with the alloy flashing. So, to follow Hardie's guide to the letter, coated alloy is suggested. Thanks for pointing that out. I do want to let you know that I use regular uncoated with absolutely no adverse effects, and my oldest siding jobs are 15 years old now. I've had occasion to remove siding (for different renovations and add-ons) and the a decade later the alloy flashing under the joint was still shiny. The Hardie guide can be seen at jameshardie dot /d2w/best-practices/intro-tools-hz5-ca-en.pdf

[@qmax-en5ry]

+James Glass well I didn't know either that aluminum will corrode when is in contact with concrete, few years agoI had the experience of removing a laminated wood floor that was installed 2 or 3 year before,it was just a simple repair around the AC unit,and we discovered that the installers did not used underlayment in that particular area, and it was nothing left of the aluminum sheet under the laminated floor other than dust

[@JamesGlassJamesGlass]

+qmax1969 I'm glad you brought this up--and I want to share another link on why alloy (and other non-ferrous metals) sometimes go to shit around concrete and others times the don't. Here's a paper on just that: copper dot org/applications/plumbing/techcorner/pdf/corrosion_nonferrous_metals_contact_concrete.pdf Take note that youtube won't allow urls in the comments, so yesterday and today I had to use the world "dot" in place of the symbol! When extreme wetness and/or alloy is immersed in concrete a galvinic reaction can happen if the alloy is allowed to react by an electrolyte bridge. More on that in this article: aluminiumdesign dot net/design-support/aluminium-corrosion-resistance/ Underneath a caulked Hardie joint, and in the vertical position where water sheeting can prevent water from pooling (unlike the horizontal layment issue you had with the underlayment) there isn't enough water to form an electrolyte bridge. James Hardie is being abundantly cautious in suggesting coated alloy be used, especially since their product is installed in coastal areas where horizontal rain is an issue. So, knowing the science (as I do) is vital in understanding why (a) Hardie is overly cautious and (b) when and were alloy can be used around concrete. But, like I said, you're not wrong. And there is no downside, except a bit more money, to using coated flashing. Where I live, coated alloy roll flashing is a bit more than twice the cost. We do have issues here with folks installing trim coil over pressure treated lumber without the appropriate vinyl barrier. Even thought the trim coil is coated, the coating is breached it's not enough. The trim coil just gets eat up, especially if the lumber behind the trim coil is often wet. But, you're not wrong, and you've inspired me to stop being cheap even though using uncoated flashing hasn't ever been a problem. I retired now, but I'm sure I'll still hang siding in my life, and I think from now on I'll just pony up for the coated. Why not? But, it's important to know the science, and why Hardie suggested coated even though it isn't always necessary.

[@toonybrain]

Hardie no longer recommends caulking the joints due to deterioration-of-caulking issues, and probably because of the flashing.

[@taron.y]

I stay away from felt and "metals with a high gloss". Best to use a color matching flashing so when your boards open up a bit there is one continuous color for the eye to see...the little things...oh and moderately tight butts...

[@jayscanlan2775]

one might spray paint the flashing behind the but joint with a closly matched color

[@jayscanlan2775]

its also recommended to prime the siding but ends

[@ameyc2]

Taron Young can I go in and place flashing post installation I don't think the contractor flashed the butt joints he also Caulked them I hear this is a no no?

[@myse5a]

Notice in the video that James is so worried about the flashing between gaps of the hardie yet the outlet he cut out is gapping the two sections of hardie. It leaves a gap as the upper hardie board pushes out the bottom of the in use style cover for the recepticle. Please anyone doing siding, leave us electricians a flat surface to mount our boxes. We need to have a water tight seal just like you do.

[@JamesGlassJamesGlass]

It's made flat with a shim cut from Hardie. In old work situations like this, one sometimes inheirits less than ideal conditions, but a good craftsperson can come up with elegant and sound solutions in the field.

[@bty1471]

Bear Skin is the way to go

[@lexwaldez]

Second this - nonreactive plastic sheet that hangs easily and is cheap. Rated for 20 years and made in USA. Good call B Ty!

[@chinabrown5459]

I will use Bear skin

[@peterbud7278]

Framing gun?!?

[@aireservofchesapeake3370]

Sure wish my home builder would have properly flashed my Hardy Board siding. Not a comfortable feeling that it is not. Some contractors do ANYTHING to save time...

[@jacobhufnagel1140]

You can simply use a 1/4 in H Channel cut to 8 in.

[@grandpapops6692]

Good thought

[@RobertWillis-mw9nd]

I would not use non treated pine under or around windows!

[@combsjboyvirgo]

Caulking is never advised for hardie.

[@cmjsparky2618]

Thats only on the color plus hardie boards. Nobody wants to see the joints caulk police

[@JamesGlassJamesGlass]

Is this an advertisement? I think it is! Despite the obvious marketing, I'll go check the link. If it looks promising I won't delete this comment.

[@davidbarry3469]

Sorry, Bad advice.You should be using a water barrier under the cladding and mounding the cladding on rain-screen then no calking or flashing is needed.

[@JamesGlassJamesGlass]

Well, I don't control those suggested video--that's all youtube! Thanks for the feedback on my videos though!

[@allenstone8731]

Black 30# building paper works just as well and is actually easier to work with.

[@roberttitus3406]

#30 the ticket

[@PerryTradesman]

great job, great idea!🇺🇸

[@roberttitus3406]

Paint will fail if butt joints are caulked

[@cookinitmax]

I went to the hardie web page they don't recommend leaving a gap between each Hardie board they actually want you to go ahead and butt up the Hardie board to the other Hardie board without any gaps only leave gap when butting Hardie to wood silicone at this time is recommended. Hardie board doesn't swell or doesn't expand like regular hardwoods or woods so that was their recommendation they don't recommend using any silicone when butting up to Hardie to Hardie. Not my recommendation. I didn't go to You Tube to find out how to I went straight to the source James Hardie him self the inventor.

[@davidrandisi9562]

Why is there even a seam right there? Lol

[@darryltaylor9916]

That was my first thought.

[@JamesGlassJamesGlass]

Flash all butt joints. (But don't flash your butt!) I've only installed Hardie shingles and planks!

[@brookbandeen4999]

Any professional Fibercement siding installer would never use unpainted aluminum flash! Pay an extra 3-cents for some cheap painted aluminum

[@JamesGlassJamesGlass]

You're right. I no longer do it this way.

[@chinabrown5459]

I am going to use Bear skin from Amazon $ 32 for 50

[@JamesGlassJamesGlass]

I'd like to see that article, and I'd like to know the author's justification for skipping caulking, which is the first line of defense against rain. If you have a moment, could you please e-mail that article? jamesglass jamesglass org. I do not skip caulking. Plus it looks better!

[@jimclark7917]

Joints aren't to be caulked per hardie instructions

[@JamesGlassJamesGlass]

I should laugh--the PDF does say this, but honestly in this climate we don't prime but joints and we rarely field dress PT cuts. We're losers, I know.

[@johncasoni4379]

Do NOT caulk butt joints!

[@JamesGlassJamesGlass]

Hardie has a few things to offer on this (this is an interesting thread): www.finehomebuilding.com/forum/hardieplank-caulk-at-butt-joints-failed-what-to-replace-it-with So, yes: butt joints are no longer caulked because of failure. What the Henkel guy wrote is good.

[@markdeezy1]

I use tar paper. even cheaper

[@nateestes2039]

mark dulisse I use weather guard which is used in valleys for roofing has a backing you can peel and stick to wall will never come out like cheap tar paper

[@jul9cuz]

Butt Joint

[@JamesGlassJamesGlass]

Haha.

[@fergferguson7370]

Hack job..

[@howierasmussen]

You don’t caulk the butt joints lmao 😂

[@louiegarcia7527]

talk too much.just illustrate it my friend