what I am saying is that Magnum Board is not an approved substrate for hardie siding

I'm not talking about using the James Hardie board at all. I was wondering if anyone has used the magnum board siding instead of James Hardie board. I guess I should have been more clear in my previous post. Sorry.

I have installed Hardi-Board siding. We had this scissors like tool, that would eat away a small strip to cut the boards, with no dust and clean edges. It is brittle, as in you can't drop it or step on it, or pick it up by only one end, but if you are careful there will be no problems. On a house we worked on, we only broke a few, and cut them to use elsewhere.

Fiber cement shears , they work great ...much better than a saw

Has anyone in the North East installed JH siding directly to OSB without using Tyvex? It seems to be OK according to the installation guide but generally reading online ... it seems like a bad idea. RR

Its a bad idea to install any siding without a vapor barrier in any part of the country

Hello all, firsttimer here
I am currently building a house in Vancouver, BC. We will be using Hardi or Certainteed fibre-cement panels. Here on the 'Wet Coast' building bylaws require us to have our exterior finishing to be built as a 'rainscreen' system. Basically it will be fibre cement panel, 1/2" treated plywood furring strips, building paper/Tyvek then wall system.
My wish is to install the panels in 4x8 sheets with 3 or 4 inch battens at the butt joints. Has any or you done this on a rainscreen wall? My concern is the horizontal joints where there is no continuous backing (for wall drainage) will not be as moisture resistant as the vertical joints that are nailed over the furring strips. These furring strips are placed at 16" O.C.

For the most reliable results, you should obtain the longer Hardi-panels in order to avoid having horizontal joints. They can cause you headaches in the long term because the panels expand and contract as the temperature changes which could eventually lead to edge damage and water penetration.

If you have to use the 4'x8' panels, especially where there is so much precipitation, you might want to make a lap joint with some kind of structural support behind it such as a 2"x2" cross member to keep it structurally ridged. Don't forget that, especially in your wet environment, it's important to keep the edges of fiber-cement panels and trim above the soil and standing water to prevent them from being damaged.

I may consider instead of horizontal battens to go with a z-flashing extending form between the building paper and furring strips to overlap the lower sheet of fibre cement board. This way I can add more furring strips (closer than 16" O.C.) and still maintain the rainscreen drainage. Yes, I will be using as long a panel as is available. Thoughts?

Hardie recommends 2-1/4" nails galv 'headed' nails, anybody use finishing or box (smaller headed) nails?

I think z- flashing could work as long as it has a good amount of overlap on the bottom panel and under lapping of the top panel. You could probably use soft aluminum flashing and shape it into a very gradual z. It would be more durable than plastic. (Copper flashing is the most durable although expensive.) But, what ever you use, keep in mind that the edges of Hardi-panel and Hardi-boards tend to wick moisture. On the upper panel, you might consider sealing the edge and up both sides a couple of inches before installing it. A lacquer base primer will soak in seal well.

Allow enough gap between the panels for any expansion. Even with z-channel, there has to be room for movement. The longer the panel, the more it could move. My studs are 24" on center and I used Hardi-panel over Tyvek without a problem. So, your 16" center studs should be just fine. You just need rigid support behind joint and flashing to keep it from flexing in the wind and you guys have some powerful winds there sometimes.

For the purpose of nailing, think of Hardi-panel like it's drywall. It's a soft material and finishing nails will pull right through it. You have to be careful with even large headed nails because its easy to drive them too deep. This can be a problem if you use an air-nailer. If your Hardi-panels are to be installed by a contractor, make certain they know how to do it or they will be shooting nails through it. (I also recommend staying out of the house while they are installing it. If they miss a stud, the nails will go through the material like it doesn't exist and shoot through the house like bullets from a gun.) If they drive the nails too deep into the Hardi-panel, they won't hold it securely and can pull through just like with drywall.

For the horizontal joints, If there is sufficient z- channel overlap and under-lap AND your furring strip is wide enough to support both the upper and lower panel distortion, I would let the edges float. Nail the panels onto the studs where the nails will be covered by the battens. Nail the flashing through the under-lap where it will be covered by the panel.

Hardie vertical siding is available in 10ft. lengths to minimizing horizontal butt joints, when they are necesary keep them near the top so overhang heps to protect joint from elements. as shown on this house with 4 ft. overhangs

Anyone have any recommendations on specific paints, specifically low or no VOC's that you have had success over Hardie siding?  I am doing a job next week and would like to be able to recomment something to the customer.  It is not the first time I have used Hardie siding, but the first time the customer has been concerned with the "greenness" of the paint.

Thanks a bunch in advance.

Any paint, no matter how "green" takes energy to produce, energy to ship, energy to store, and energy to apply. Even "green" paint has a high carbon footprint by the time it gets to your house. The less paint you have to buy, the truly "greener" the product is. So to have the greenest possible paint, the best idea would to get the longest lasting and best coverage paint in large containers(like a 5 gallon bucket). The container can be reused instead of trashed, and not having to repaint as often will reduce the overall impact.

Durability > "green" marketing

It would be "geener" just to buy the pre painted hardie, as they buy in 55 gal recyleable drums, save on shipping, save on the painter making multiple trips to your job to apply it, no paint buckets to get rid of

We are using both low and Zero VOC paints from Sherwin Williams brand on the Hardie Trim and the indoors for our project.

Marcierizzo,

Can you furnish us your definition  [or a definitionof] a low-no Voc product? Curious about where that's written in the "Green Bible"

All very good points on the transport and packaging of the paint. The customer has already purchased the Hardie siding, so getting the pre-finished is no longer an option. As far as the low/no VOC's, I have yet to find this elusive "Green Bible" with all the answers. ;) When I do, I'm sure we will all have a good read. I have used Home Depot's interior paint, Fresh Choice. It does not have VOC's in the tint either. Thus making it a truly "No VOC" paint. Others claim to be low/no VOC's but then put traditional tint in it and thereby negating its claim. I was very happy with the Fresh Choice, but it is only interior.
Basically, I was trying to weigh the options of traditional paint vs. low/no VOC's. If the traditional paint lasts a significantly longer time, is it worth using it to decrease the manufacturing/shipping issues of having to repaint sooner. Hopefully that made since.

Thanks for the input.

Hardi Siding is a good product. Prefinished is the better option. If you are in a climate with large temperature changes you may want to limit chalked joints. Divide your wall with more trim pieces, similar to a batten board look. Long runs of siding butting end to end with chalked joints seem to pull apart over time. Break long runs up with a trim piece does help. I know this may be hard to visualize. 

The low VOC paints can be as durable as any other paint. I like the low VOC paint for inside painting because it has very little odor. For outside painting, it's not as important unless you are sensitive to volatile organic compounds like mineral spirits or turpentine. The amount of VOCs released into the atmosphere is pretty insignificant considering the lifespan of the paint. I have noticed also that low VOC paint doesn't seem to have as long of a shelf life as oil based paint.

As far as what type of paint can be used on fiber-cement board, I, myself haven't heard of a paint that won't work. If it's not primed, it will suck up paint like unprimed drywall which why you want to use a very good primer. As a plus, you can have the primer tinted. The right tint can enhance the color depth of the top coat and it will last longer because wear won't show as quickly.

Sometimes, the location of your house can be a factor in choosing a paint. If you live in a very humid climate where it rains frequently you may need an exterior paint that dries and hardens quickly as well as resists mildew. Latex and low VOC type paints take longer to dry. How long the paint wears has a lot to do with the amount and type of solids in it, usually clays and minerals. That's why a lifetime warranty paint tends to be thicker than a 15 year paint.

For the best results, decide what qualities you would like your paint to have and how much you can afford. (Some of it is very expensive) Then go to a reputable paint dealer. If you have any literature describing your fiber-cement board, take it with you. James Hardi isn't the only manufacturer. So, your paint dealer will most likely have factory recommendations for the best type of paint to use.

I am an  general contractor and would like to express my dissatisfaction with the James Hardie company and it's products. 

First off, the lap siding products are the most labor intensive of all siding products on the market.  It doesn't help that they have extremely poor quality control regarding dimensional integrity.  I'm currently working on a job where about 50% of the lap siding product needed to be re-cut at the ends because the factory cut was over 1/8" out of true square.  Needless to say, this will be my last job with James Hardie product.  They may be the largest fiber siding company but definitely NOT the best!  The concept is good and the product will last longer than wood, but it is basically cardboard dipped in cement which will not withstand a good hail storm.  I've seen hardie siding with holes in it due to hail!  Here in Texas, hail is big issue, and Hardie tries to suggest their product is safe from hail.  But if you read the warrantee closely, they basically take no responsibility if anything happens. 

In addition, they decided to change the primer recently and apparently didn't notify anybody including their sales rep!  This fiasco caused me to receive two different lots of lap siding with different primer on the same job!  Needless to say, the customer is pissed because I had to use mixed panels on the same wall of the house!  When I tried to contact James Hardie about this issue, they sent me some form letter saying the changed the primer due to technical advancement, but neglected to say what the "advancements" actually did for the customer!  It was obviously changed as a cost reduction.  Otherwise, they would have spent more effort getting the word out about the benefits.

Whatever you do, thing long and hard about using this product on your home.  The pre-painted version may be better, but the pre-primed stuff you can get from Home Depot of Lowes is not user friendly and may not be what you expect from their "fluffy" literature!