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New siding and housewrap

ekard | Posted in General Questions on

Hello, climate zone 5 (Boston Area) I removed cedar siding around my windows and I realized that a large portion of the plywood probably 1/4 of the entire wall is completely rotted and needs to be replaced with new sheathing (this will be done with 7/16″ ZIP).   At this point I plan to take the rest of the siding down and put up all new siding (want to use LP Smartside).  Unfortunately I won’t be able to put continues rigid on the outside due to no overhang, etc. This wall has a bunch of line-sets from my Mitsubishi heat pumps that are going to be a pain to side around so my questions are as follows:

1) Can I put the line-sets into the walls or will that create problems?  I hate screwing the line-sets into the siding because I feel like its just creating another place for water to enter, unless there is a good way to flash or detail them?  Everyone in my area that has heat-pumps has vinyl and I can’t find any good details on how it should be done with a hard siding.

2) Where the existing sheathing is still good, I was going to use Blueskin VP 100 to cover it and use Ben Obdyke Home Slicker as a rain screen BUT the local LP rep. said just going over the ZIP and plywood with HYDRO-GAP  house wrap is sufficient.  I think the Blueskin/Zip would at-least give me more energy efficiency by stopping the air leaks better.  Any thoughts would be helpful.

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  1. user-2310254 | | #1

    You are planning to tape all the seam on the new and existing sheathing, correct?

    This video ( compares three types of housewraps and suggests (to me) that either Hydro-gap or Home Slicker would work.

    Maybe some of the building professionals will chimed in with some practical advice.

  2. jberks | | #2

    It reads like you want to use the home slicker in lieu of furring. Is that correct? Does the current assembly not have furring strips?

    I personally prefer to use 3/4" furring for a bigger air gap, and more drying potential vs the 1/4" gap the slicker provides. But I don't have any personal experience, with both. Maybe someone else can comment. Also things like home slicker are stupid expensive out my way, so I usually don't consider it for price reasons.

    1) can you post a picture of your lineset and siding?
    Yes you can put linesets in your walls, just make sure they're well insulated and sealed. It's normally not difficult to detail the penetration in hard siding with a bit of fancy carpentry work.

    2) if you're already using zip, you might as well take advantage of its wrb and not bother wrapping the whole house over with another wrb. I suggest blueskinning or liquid applied membrane to the old plywood and then it makes transitioning to the zip that much easier as you seal the seams and screws on the zip. But not being to see your project, it might be easier and cheaper to just hydrogap wrap the whole thing. That's your call. If that's the case, I'd still air seal the plywood with tape or sealant before the wrap again, my personal preference in the pursuit of building tight.


  3. ekard | | #3

    Steve to answer you question, "yes" at a minimum I would be taping all of the seams of the sheathing on this wall.

    Jamie to answer your question "yes" I would be doing the Home Slicker in lieu of strapping because I have a flush gable end on this side (no overhang) so adding strapping would require re-doing my roof which isn't an option right now. You can see in the pictures where I have replaced the rotted sheathing with ZIP. I had an old roll of black felt so I covered the plywood with that since its going to rain tonight.

    I was originally going to go with Smartside siding but the sales rep. said I would have to change all of my trim to 5/4 because it sticks beyond 1x trim. I'm backing away from that idea since it would require me to change all of the trim on the house in order to look good. I also got a crazy expensive quote to disconnect the Mitsubishi Mini-split line sets and put them into the wall cavity. So for siding, right now I'm looking at doing either Cedar bevel clapboard siding on-top of Home Slicker on-top of Blueskin VP100, Cedar bevel clapboard on-top of hydrogap (the hydrogap would also cover the Zip and plywood with taped seams) OR Hardie Siding on-top of Blueskin VP100. My only hesitation on the Home Slicker product is I haven't installed that before so I don't know if it would be rigid enough or if it would look wavy. Let me know thoughts on this.

    In terms of the line sets I think it probably just going to be easiest to put good mounting blocks and flashing where the head penetrations come out of the walls for the line sets. If I go with Cedar siding I just need to make sure I pre-drill carefully for the line set covers because cedar splits so easily.

    You can see on the pictures, there is still a little bit of siding that I still need to take off.

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