Hi, I am new to DIY but want to learn. I have a couple questions about Hardie-plank. 1. How to figure out how much we need for the whole house. 2. My house is only 2 years old, the siding is just a T-1-11 I wonder is I can just put hardie-plank on top of T-1-11. My house is by the road, getting pretty noisy some time. So I thinking maybe hardie plank will help reduce the noise too. Any advice please feel free. thank you.

Hardie plank is in fact a bit of a moisture-reservoir like stucco or brick, and as such probably should be back-vented with a rainscreen cavity in most climate zones (installation instructions for Hardie notwithstanding). The back venting cavity need not be more than 3/4" (1x furring strips should be fine.) There have been reports of material interaction with Hardie siding with some broadsheet housewraps (I haven't seen it personally- can't vouch for it) but standard felts should be fine (they're waterproof but vapor permeable, which will allow outward drying of the T1-11.)

It might seem like a PITA, but it'll be worth it in the long run. In many (most?) installations the T1-11 is structural- stripping it isn't an option unless you then apply more sheathing.

Any mass you add to the wall will cut noise, so high mass siding like Hardie should help. How many dB depends a lot on the rest of the structural details though.

Mountainlake,

Just to give yourself a factual understanding of the Hardi product and avoid any advice that comes with a caveat, you should probably take a look at this!
Legacy Report NER-405 . Published by ICC Evaluation Services. Just Google NER-405
Everything you ever wanted to know about Hardi is there. Depending on where you live, you need to pay special attention to the nailing instructions if wind speed is going to be an issue for you! Good Luck, Glenn

Thank you Dana1 & Summers for your advised. I will have to do my home work.

Thank again.

To answer the question you asked, measure the length by the width by the height. So say as wall is 40' long 10' tall that is 400 sq feet. All exterior materials are measured in squares (10x10) hence 100 sq feet. You can put Hardie over the T1-11 but you will need a WRB, Tyvek, Typar and you must follow the Best Practices manual published by James Hardie, www.jameshardie.com. Noise reduction is always "iffy" with products, you have windows, doors, and the like that contribute to the issue. I would not replace the siding to help contain noise. That would be a seperate issue. Jerry H. www.constructionaheadinc.com

I recently installed 18 sq. of Hardiboard lap siding on my house. I measured the total surface area of the walls to be covered minus the window and door area and added 10%. I ended up with only 4 full length pieces of siding in the end. My supplier will take back any unused resellable planks, so it wouldn't have hurt me to over estimate a bit. I saved the few leftovers for any future repairs that might be needed.

just curious as to the cost per square? 

Labor or materials Subcontractor price or GC price? What area of the country? JH

retail, materials only, northeast.  Suppose I could just go ask my local lumber yard

No more than 180.00 per sq Color Plus we buy it for around 130 here delivered, Color Plus. Siding only 6" ttw 7.25"x12' I hope that helps. JH

hey JH  How much per sq for staggered edge 8.25" hardie?  I'm going to be building a house next year and will need someone to handle the siding.  Thanks, We are in columbus ohio; the building project will take place in mt sterling ohio  43143  about 30m tops south of columbus.

Joe

Install of the shake is $235.00 per square, the materials can be purchased through us or you can source. We would charge around $550.00 per square staggered edge shake James Hardie ColorPlus. The total per square would be $785.00 for shake only. The trim and the like are additional lineal foot cost. Check out www.nichiha.com and see what you think of their shake panel. It is thicker and looks more realistic. The Nichiha would be a similar price for a more premium product in my opinion. Columbus is no problem fr installation. We are in Brooklyn, New York today and down to Raleigh, NC end of week.
We offer 15 year labor and materials warranty on all our projects.

Regards,
JH

Try;

quietewall,    http://www.soundprooffoam.com/soundproofing-a-wall/soundproofing-wall-retro-best.html

Unless your going to invest money into some good tools and you're a real quick study I think fiber cement is a little much for a DIY; at least an installation that will last and look good on your house.

As long as you're siding the house, it would be an excellent time to add 1" or 2" of XPS (like Styrofoam) to the wall. First, find & mark the studs, install the XPS, install 1x3 strapping, screwed into the studs, then install the siding. You may never have another opportunity to add insulation as easily as you can now. You can probably find details for doing this on the Journal Of Light Construction (JLC) archives.

PS: It will definitely help the noise transmission, much more than siding alone.