I have a small cinder block home built in the 1950’s. I live in central Virginia. The exterior walls are cinder block, 3/4″ furring strips and sheetrock. No insulation. The attic is vented with insulation batting between joists. The crawlspace vents are sealed, it’s very dusty, no water/humidity issues. The house is old and leaks air between the house and crawlspace well on it’s own. No insulation in crawlspace.
I was looking at doing exterior insulation with vinyl siding. I would like to use Zip Insulated Sheathing. I would get continuous insulation, avoid furring strips and have a nice, clean surface for siding. The exterior of the house has been painted god knows how many times, I can see 3-4 colors if I scrape it a bit. But I have couple concerns and questions.
Should I use a fluid applied water/air layer before attaching the Zip? I’ve seen diagrams that show using a layer but that was for attaching rigid foam and furring strips, then hanging siding. I am not sure the same applies since Zip sheathing has it’s own air/moisture barrier?
How should I attach the Zip? I’ve asked several contractors and got all kinds of answers. Glue it and screw it (Tapcon style). Glue and nail with concrete nail gun. I have 2 problems with both these methods. I’ve tried to use Tapcons and the blocks just crumble too easy, they never attach well, they just drill out a hole. I don’t know if it’s the age or style of blocks, but both nails and screws don’t attach well. I’ve gutted and renovated almost all the interior and the existing furring strip (originally nailed) are lose. I have to often reattach them. The only thing that seems to always work, are large rawl plug style anchors. That would be a nightmare for sheathing. Maybe there are better anchors? Perhaps the glue with some anchors holding is enough. Or use a couple rawl plugs for each sheet, then use other anchors?
Thanks ahead for any advice…
Replies
I don't know what the exterior of the house is currently. But I would have focused on putting the insulation on the inside of the house. On the outside you can quickly exceed the depth of the rake on your gable end walls which could be 2x's. If you bump that out then your shingles won't cover the extension.
If I understand you correctly I think that you are concerned about what it costs you to heat your home. May I suggest leaving your walls alone and getting different heat sources? Maybe a wood stove to compensate for heat loss? Or 3M window film? Based on what you are willing to do I think this may be to minimal but I thought I'd put it out there. Insulating the basement may help keep you floor warm which would matter to me. Blow some more insulation into the attic and live with it. It won't be terrible.
My parents house was the same way and it annoyed my father to no end but the outside of their house was brick. When he remodeled a room he would put rigid insulation on the wall and an extension jamb on the windows of the same depth. He also put in Pella windows. They were/are great for r-value, maintenance and noise reduction; which was a surprise benefit.
If it were my house that is probably what I would do, the same. You have to figure out what it is worth to you both emotionally and financially to do this overhaul. You may have better things to do. My parents house turned out fine but he did burn more oil than he wanted to. So there you have it, floors, ceiling and windows. Pressure wash and paint the stucco (that I am guessing you have) and I think your house will give you what it needs to. Best.
No stucco, just painted block... I wanted to put vinyl siding up and thought it would be a good opportunity to add insulation...
The house is very small, 800 square feet with a 12x12 screen porch.. inside insulation just isn't viable... I've already gutted and renovated the kitchen, utility and bathroom..
I only have a heat pump, all electric... no alternative heat source.. there is an abandoned oil fired system in the crawlspace... I have a small chimney but no fireplace.. gas isn't available so I'd have to get propane tank and find a place for a new gas fireplace.. so that presents it's own issues... my electric bill in the winter is $325-350...
I thought since the house was so small, I have access to scaffolding and have done all my own work, why not try the zip sheathing.. was looking at the 1 1/2" Zip to avoid roof issues... looks like it should work, the gable end has old, painted shakes over sheathing that was mounted off the face of the block... if that makes sense...
Wames,
I recently competed a project in which we applied 1.5" of foam to the exterior of a house constructed of block. We nailed the foam with masonry nails and have had no problems to date. To prevent rainwater from getting between the foam ànd the block at the windows, we used fluid applied membrane at the entire sill, bridging the gap.
If you haven't already, think about how you'll detail the windows, as they can be a bet tricky. It seems like the vinyl return from the face of your sheathing back to your window frame could use some attentiom. We furred out with 2×4 at the perimeter of each window and door to have a bit of nailing surface at the returns (the exterior finish was stucco in our case).
This has been rolling around some in my mind but I am busy to so perhaps I could think it through some more...
You could start out where you will get the most bang for your buck, attic insulation. You can install the styrofoam baffles on the underside of your roof sheathing in between each rafter, rent a blower from a home center along with blow in insulation and probably have that job done in a weekend. You will cover that expense quickly.
Next, insulate your crawl space. Your feet will feel warmer and that always makes me feel warmer.
I don't know if money is tight or not( and I don't need to) but really you don't have to keep your bedroom heated if you are not in there but to sleep. Get yourself a heated matress pad. Sounds funny maybe but I'm just putting it out there.
With a propane stove. Some of them side wall vent. This could save you the cost of a chimney. If you can't place it on an outside wall you will need stainless steel once you penetrate the roof and go outside.
Also, I would recommend buying the propane tank. Companies will "give" you a tank if you buy their propane for 10 years but trust me, you will pay a higher price per gallon especially if it is buried. A hundred gallon tank would be fine and you could use that to also fuel a grill on your nice porch that you were talking about.
I have a wood stove and although I don't know when it will ever pay for itself (primarily because of the stainless steel chimney there is enjoyment that comes from having a fire. Let's not forget about having a good time along the way.
I am remembering a house that I built and the woman who bought it said she wanted to install a gas stove, I didn't think too much of them until I saw it burn. It was a great choice for her. Push a button and get the fire and justify it with the heat. In that order. She bought a Vermont Castings stove in red. It was gorgeious.
Another option for you is to at least check with your local utility company and see if there are rebates for you insulation work, probably not but I would inquire about an averaged monthly utility bill. By that I mean you add up all your bills for the past year and divide by 12 and agree to pay that amount every month so it is easier to budget.
In this case you will be over paying because the work that you are about to begin but you will get it back or in a couple of months they will re-balance your monthly payments.
I was wondering if there was such a thing as liquid insulation for the inside of your block so I did a search and found this.
https://www.youtube.com/watch?v=_dOm0a4unEw I don't know if your cinder block is 2 bay or 3 but this is certainly an option. If you could find a way to apply some plaster lath to the outside of your home the plaster would help to shield your home, and block, from the elements. Good luck! Enjoy your space!
You will do well to add insulation before siding. It's your one opportunity to do it if you are about to do siding anyway. Zip is a great product and they will have their own recommendations on detailing. Ask them for a window return detail.
I h owned a block house for 10 years they have great thermal mass which helps to even things out so you really want to keep the inside at one temperature and not turn things up and down.
Your best bet with Zip is to use furring strips on the block (CMU) you are going to have to experiment but try masonry cut nails( these are the hardened ones not the same as the ones used for flooring.) You may have better success sinking them into the mortar joints and not the block itself.
Another good option is a HIT anchor. They install quicker than a regular expansion anchor and I've had good luck with them in the past.
Make sure that you are drilling the correct size hole for the anchor! And a SDS hammer drill (even the cheap Harbor Freight one) will make your task much quicker.
Thanks for all the ideas everyone! I hadn't checked back for a bit and my email never said I had responses. I thought no one had chimed in, so thanks again!
The window return detail is one I've been mulling over in my head for some time. I had my windows replaced a few years ago and I took a ton of pics so I had a good understanding of what I have to work with. I have some ideas and I think the liquid applied membrane will be my best bet at keeping water out here. Luckily, the old windows had a large brickmold surround that was left for the replacement windows. I have almost 3" around to work with, so I think that offers more options for the window return detail. I reached out to Zip for some information. I found some details but wanted to get some verification from them.
With keeping my house at 68-69 during winter months and still paying $250-350, I need to do something. I am planning to seal and insulate the crawlspace walls and encapsulate in the next couple months. Before we hit the colder months. I want to see how that helps. I have insulation in the attic but I plan to seal any air leaks, a cheap fix there. My attic access is already boxed out, sealed and insulated too.
Do you know if the block walls are hollow or filled? My house is similar, but farther north in NJ, with hollow block walls. After removing attic floor insulation it became obvious that the walls are hollow and were serving as a nice chimney bringing warm air from the first floor of the house into the unconditioned space.
I'll be interested to hear what you decide regarding wall insulation. Rigid foam over furring strips definitely seems like the preferred approach for CMU walls.