Uninsulated closed walls can lead to overtaxed heating or cooling systems, high bills, and energy waste. To improve thermal performance, there are four main methods of adding insulation to existing walls: adding insulation layers, installing insulated drywall, or using decorative thermal panels. Measure the total area of the walls to be insulated before purchasing fiberglass insulation batting.
Insulating a room from the inside can be done by adding insulation layers to the existing walls, installing insulated drywall, or using decorative thermal panels that enhance the room’s aesthetics. Before adding insulation, assess and address any signs of damage or issues and consider the type of insulation that suits your needs and budget. Loose-fill insulation is the best option for adding insulation to existing interior walls, available in materials like mineral wool, cellulose, and fiberglass. It can be blown into a small hole cut into your drywall, minimizing the amount of work and mess involved.
Roll insulation is the traditional method of adding insulation to cavities in walls, but the walls are already closed. If the drywall is down and the wall cavity is exposed, open cell spray foam can be applied. Teflon lamination wall paints provide insulation, which is slightly expensive but worth it. Certain types of insulation can be installed directly into a wall through small holes, including injection foam and blown-in insulation.
Blown-in insulation involves drilling holes in the walls and using a machine to blow insulation material into the walls. Expanding foam insulation, such as polyicynene or polyurethane, is an excellent option for sealing air leaks and insulating hard-to-reach areas in old houses.
📹 How to Insulate a Wall Without Removing the Drywall | Foam University by RetroFoam
Did you know insulating walls without removing drywall can be done with ease? Here’s everything you need to know about how to …
What is the cheapest way to insulate an existing wall?
The most cost-effective method for insulating internal walls is typically through the use of materials such as fiberglass or cellulose, which are less expensive than foam insulation. A cost-effective DIY project is the installation of rigid foam boards, which can be accomplished using rented equipment to blow fiberglass or cellulose into wall cavities.
How to insulate a cold wall from the inside?
Insulating walls from the inside is a common practice, but it has its drawbacks and advantages. Insulating walls from the outside is more practical due to the different reactions that occur when insulating the structural wall. Insulating from the outside shifts the freezing point towards the colder side, such as the exterior, while insulating from the inside shifts it towards the warmer side, such as the interior. This is because when the wall is insulated from the inside, it lowers its temperature to nearly the same as the outside temperature, which is the opposite of the opposite effect.
Insulating from the inside can be a more cost-effective solution, as it requires less maintenance and can be done in a shorter time. However, it is important to consider the specific needs and preferences of the individual and the building’s structural needs when deciding whether to insulate from the inside or the outside.
Do you need a moisture barrier between insulation and drywall?
In regions with cooler climates, the heating of domestic properties from the inside is a significant source of humidity. It is therefore essential to install a barrier between the drywall and the insulation to prevent the accumulation of moisture within the home.
How much does it cost to insulate a wall without removing drywall?
The average cost to insulate a wall without removing the drywall is between $1 and $4 per square foot. The least expensive insulation materials are cellulose and fiberglass, while the most expensive are blown-in insulation blankets and spray foam insulation.
What is the easiest way to insulate interior walls?
Batt and loose-fill insulation are easy to install in existing homes, but adding insulation to existing walls requires deciding if you want to open up the walls. Loose-fill insulation, such as fiberglass, cellulose, and mineral wool, can be blown into the wall through a hole of 1/2 to 2 inches without tearing the whole wall apart. This form is more efficient than batts as it fills in tiny spaces left open by batts.
Injection spray foam insulation is another option for insulating enclosed cavities in existing interior walls, creating a more airtight seal even if the wall already has insulation. This material is different from standard spray foam insulation, which can only be applied to open walls.
Is it a good idea to insulate interior walls?
Insulating interior walls in your home can enhance energy efficiency by preventing temperature swings that can crack drywall and retaining their temperature longer. This is especially beneficial for rooms that aren’t frequently used, such as guest rooms or storage rooms. Insulation options include fiberglass batt insulation, cellulose, spray foam, or rock wool. Fiberglass insulation is DIY-friendly and inexpensive, but requires exposed wall studs for installation. Blowing cellulose insulation into existing walls is the least invasive method for insulate pre-existing interior walls.
What is the cheapest way to insulate internal walls?
Insulation boards are a popular and affordable method for insulateng internal walls, as they are easy to install and relatively inexpensive. Battening the walls and building a stud wall are other affordable ways to insulate walls, but they come with their own costs and benefits. Battening the walls can help reduce heat loss and improve air quality, while building a stud wall can increase insulation’s durability and reduce the need for costly insulation materials. By implementing these methods, homeowners can make their home more energy-efficient and comfortable.
How to insulate walls in an old house?
To insulate the walls of an existing dwelling, one must first apply a house wrap or vapor barrier, then attach foam board insulation, install siding, replace the existing windows with units that are more energy-efficient, caulk the window trim, and finally, use weatherstripping to reduce air leaks.
Can I insulate my walls without removing drywall?
The most prevalent method for installing insulation without the removal of drywall is the drill-and-fill technique. This method involves the direct injection of insulation into a sealed wall cavity through small apertures created in the wall.
Can you add insulation to existing interior walls?
Insulating walls can reduce energy costs, drafts, and noise. Air seals offer comfort by reducing airflow through walls. Protecting your entire house from air movement can save even more money. Spray foam or injection foam insulation can help keep your home cool and warm during the summer. Both methods can help save money and provide additional comfort. Overall, insulating walls can significantly improve your home’s comfort and energy efficiency.
How do you insulate an existing internal wall?
Solid insulation boards, backed with plasterboards, can be installed directly to internal brick walls, providing multi-purpose insulation and superior performance. Available in thicknesses between 10mm and 60mm, these boards are attached using plaster or adhesive and sealed between joints for airtightness. They are suitable for flat walls, but uneven walls should be insulated with batten walls. These boards are available in various sizes and are designed to resist moisture penetration.
📹 Blown In Insulation Installed Into Existing Walls.
Blow in or Blown in insulation installed to a house with existing sheet rock walls. We hired out the work to be done but this video …
Thanks for the article info! Been thinking about insulting my already finished garage walls and was considering blown in insulation. I only have one full 24’ wall, one 24’ minus the garage door opening, and then about an 8’ wall section, the rest borders the house and is already insulated (it irked my nerves that the contractor didn’t go ahead and finish it out when building the house, it would’ve probably only cost him an additional 1-2 hundred dollars to do so, but that’s a nickel saving contractor for ya!). One issue I’ve already previously considered is the air displacement as I’m doing it; I would think you would need a smaller sized hole above the one for blowing it in to help alleviate blow back which was blatantly obviously necessary in your article, lol. I’m thinking a 2″ hole adjacent to the larger 4″ hole (or whatever the size is with the machine rental), and then just making a small screen covering to hold over it as I’m blowing in the insulation. Then just pulling it away and knocking off the excess as it builds up. And then patch finish out both holes afterwards, similar to what your father did. 🤷🏻♂️ My other option is drilling out several small holes in each void area and going with a low expansion foam insulation, but I think that cost, and the overall time cost, would be exponentially more… Edited: btw, there’s a bonus room above the garage, and even in that aspect the contractor only insulated the void underneath the room itself, and left about a 3’ section along each side without being insulated… 🤦🏻♂️ probably not even another hundred dollars to finish out blowing it in…
I am perusal this in Feb 2023. Thank you for this article! I have an older smaller home that definitely needs insulation in the walls. I’m gonna do it myself but am still trying to decide on what type of insulation I need. And also finding out what skills I have and what I need to hire out. This helps me greatly! Thank you
Oop!. Should have numbered/labeled each hole/plug combo. Then it would have made perfect replacement leveling. Even the direction/orientation would have helped. I will do this. The only concern I have is DIY vs Pro-contract equipment. Two stage blowers are not available for DIY’rs. Wall cavities should be dense packed with two stage equipment.
Horrible! You need 2 holes per cavity. One about a foot from the ceiling and one about waist level. Fill waist level holes first then top holes. This is to ensure the cavity is fully packed. All you need is 2″ holes (I used 1″ for cellulose), and use tapered wood plugs. Inset wood plugs 1/8th in and cover in spackle. And this is only a 1 man job if you know what you’re doing. I could drill, fill and load the hopper all by myself without having to shut off the machine. The job only took as long as it took to fill the walls. By the time the last cavity was being filled, all the other holes were plugged and spackled. When I quit, I was making 22 dollars an hour or piece work, whichever was more.
Newspaper? It’s cellulose and it’s dense-packed and will NOT SETTLE when installed correctly. It’s also superior in almost every respect to fiberglass, including fire resistance, mold resistance, incest resistance (treated with boric acid) . What you “think” doesn’t matter. Higher R-value per unit of depth, too. Calling it “newspaper” just shows a gross ignorance and an attempt to make is sound inferior.
You’re paying for more than just Insulation and labor. The blower machine/hoses/ etc is $300-$600 rental. On its own. So doing it yourself would end up being cost of insulation, renting a beat up blower, probably 2-3 trips to Home Depot. And who knows what else. So don’t be too surprised when a professional crew charges what they do. 👍. Thanks for the article.
Very useful article, Thank you sir for making it. I have a 1932, two story, Absolutely no I insulation in outer walls. The entire interior of this house is shiplap, so, that being said. I’m thinking about taking the top two outside wood siding off, fill all with the pink insulation then, tac the wood siding back on. Bam! Done! No mess inside home. No holes to fix. What you think bud?
Ben, this is an excellent article to exemplify why not to blow in fiberglass! Those four-inch holes are gawd awful. Cellulose is installed with one-inch holes. The plaster patch takes about fifteen seconds. I guarantee that fiberglass will settle. It probably already has. Drill an inspection hole along the top you’ll see empty space. Agreed, anyone can do a sloppy job like you paid for. It takes SKILL to densepack cellulose and guarantee no settling! Blown fiberglass has a lowly R-value of only R-2.2 per inch while fire-retardant cellulose has an R-value of 3.8, nearly twice as effective. What’s even more important is cellulose actually blocks air infiltration. Fiberglass needs a vapor barrier such as visqueen to block air infiltration. You over-paid for a really garbage job, Ben. If they did it for free the 30% higher heating and cooling costs means over just a few years your “free” fiberglass will cost more than a professionally installed cellulose wall job. I GUARANTEE…will bet my house deed (Free & clear) against a donut, that I can install a lot more cellulose OVER the fiberglass you already have. You are doing a disservice to the public to parrot the lies told by the fiberglass industry. Cellulose packs densely into the walls…remove the drywall and the cellulose stays packed…you have to force it out. I’ll use your article to demonstrate why not to use fiberglass. Did they mention fiberglass comes with a cancer warning? We routinely vacuum out fiberglass form attics full of mouse droppings and dead mice.
Thanks for the article. I found this enlightening on how to blow in insulation in walls. I am thinking of using sheep wool insulation. Apparently, loose fill sheep wool insulation has similar insulation properties but doesn’t settle – and also doesn’t require wearing masks since you would not be inhaling toxic substances.
I do blow insulation. we use foam plugs in the walls. We also use a metal piece that connects to the end of the hose soo that all of the blow wont come out of the wall. On a 8, 9 or 10 foot wall we drill two holes near the bottom and the top cavity to make sure the insulation tight. That job wasnt done right by those guys but I did like that guy that screwed and spackled the peices back its better than using foam plugs.
this is horrible!!! no need for those 4″ holes! just needed reduce the hose from 4″ hose to short 3″ hose to a 8ft 2″ plastic hose at the end. only needed to pop 2.25″ holes in the walls and would have been able to run the hose all the way to the top of the cavity to fill the whole cavities with less mess and less patching. Them using a 4″ hose i am 100% those wall cavities arent fully filled if even 50% filled. horrible job. sorry to say but this is not the correct way to insulate walls. Just perusal these people work disgusts me. No plastic or anything to make clean up easier or containment incase paint had lead in it while drilling.
DON’T blow insulation into walls if you want them to last. I am currently fixing the mess that ‘pros’ created in my house, with massive voids, and walls they never bothered to even check were backed to retain the fill. The pile of insulation it left on the decking over my unconditioned porch has been compressing and collecting moisture for years now from it, soaking and decaying the wood with it. It would have been better if they hadn’t touched that wall at all! Pull the drywall and put up mineral batts, sprayfoam, or both. The old houses they do this to were never meant to be insulated that way, and the damage it can cause will cost a lot more in the long run than just doing it the right way from the start.
What a waste of time. The insulation is not being packed in as needed. Should have dense packed with cellulose using a 2″ hole keeping the holes in alignment. 2″ plastic plugs are readily available and chair rail can be installed over the holes, case closed better job, less messy. 50 years experience weatherizing homes. If the insulation is not packed in tight, airflow is possible in the wall cavity.
THANK YOU for including the drywall repair method in your article! I was planning to use something more like shim-stock, but looking at your article, I think the 1/4″ ply may be a better choice. I’ve been planning a project like this for several years now, and it’s reassuring to see someone else having done it this way. Love it!
Hi Ben, thanks for sharing this article. It was very helpful. However I would like to know more about the work that was done at this house work. Here are a few questions: 1. I am in Michigan – Do you know any companies that do this here in Michigan? 2. I can see this was done about 6 years ago. Would you have an estimate in terms of costs for this job if I hired a company? Please let me know. Thanks. Charles
Very well presented information. I assume this is a thermal job verses a sound control job. In any case, how does the fill stay above the hole. I am certain that gravity will cause a void. Sealing is only as strong as the weakest link. I believe each access hole has various degrees of voids (above the access hole). If this was a noise control job, it would never work.
I appreciate your article, but I am concerned about the blow back of insulation into the house. It is my understanding that this fiberglass insulation has fibers that may stay in the home and cause cancer. It is microscopic and when breathed in even after clean up it remains within your home floating in the air. I would love to have my homes outside walls insulated, but the risk to my health and the health of my family and truly anyone who may purchase my home down the road, keeps me from doing it. Was this topic anything you discussed with the company and if so, what was their response?
Dense pack cellulose has an r value of 3.8-4 per inch. That’s higher then fiberglass. It has a fire and bug retardant and dries with moisture hitting it better then fiberglass. These guys just probably didnt know how to dense pack cellulose well. It’s harder to do so they shit talk it lol. Regardless, having something instead of nothing in your walls helps a ton.
Thank you so much for the article, all this is very doable! I learned an awesome way to patch the holes: You put mud around the hole pretty thick, lat the tape across the patch with maybe 3″ overlapping each side, cover with mud, then back butter the patch piece a bit, squeeze patch into hole wich will push tape in, while also providing a backing and causing the edges to be very snug. Wipe off all excess mud and cut tape down on sides to maybe an inch, then I just cover it all with mud, once dry sand down and it’s a perfect patch, ready for texture!
I would’ve figured that they could’ve used some type of plumbing joint to make the connection a bit more sealed up when inserting the hose into the wall. Possibly get a rubber piece to go between the two they help keep the stuff from flying out. I am looking at trying to get blown in insulation done to in my pre-existing drywall, or having the radiant barrier put underneath my siding.
Just wanted to comment from a business side: their cost would have been more than $.25 a SF. That’s strictly material, then you have tax, labor (and all labor burdens like insurances etc), vehicle costs, machine costs (replacement costs as it wears down), small tools costs, overhead (phones, paperwork, office rent, utilities etc). Anyways, I’d like to know what they actually made profit wise. Their cost might be more like $.70-.80 cents actually when all is calculated.
Can you do this if you have plaster walls? What about horsehair plaster? My state will blow in insulation into my condo for FREE and apparently they will plug the walls too although they said it will need to be sanding and painted afterwards. Painting is so expensive though (I estimate up to $4-5k for my 850 sq ft apartment) so I’m looking for something less invasive.
79 dead: The Foam Insulation blaze that ripped through the Grenfell Tower, London, causing multiple deaths (79 confirmed / 120+ estimated) has prompted widespread commentary on the Foam Insulation Industry. A Criminal investigation into the Foam Installation Contractors concerned is now taking place. It appears there will be a criminal prosecutions for corporate manslaughter for those concerned whose acts or unsafe products committed the offence. In the case of the Grenfell Tower fire, the most likely prosecution candidates would be the building’s management company, and the insulation contractors and sub-contractors involved in the property refurbishment in which apparently highly flammable foam materials were fitted as insulation.
Cellulose is the higher performing insulator: 1. Cellulose is made from recycled material whilst fiberglass? Is not, 2. Cellulose is treated with boric acid which is a pest prohibitive which fiberglass is not, 3. Cellulose is treated with fire retardant which fiberglass is not, 4. Cellulose does not conduct radiant heat as fiberglass does, 5. Cellulose “breathes” dissipating moisture unlike fiberglass, 6. Cellulose is MUCH MORE sound deadening than fiberglass, I could go on & on & on…..
Whether you’re for fiberglass or cellulose, I tend to lean toward cellulose, any insulation in an uninsulated wall is going to be helpful. I know people want to argue about settling and dense packing and all that good stuff, but you are improving your home comfortability situation with any sort of insulation, rather than none.
Well, I’ve never done anything like this, so my opinion is probably worthless, but I need to do something about the summer heat, and I don’t want to spend that much money. This means I’m thinking of filling the walls myself with blown-in insulation. My mobile home is sheathed in horizontal vinyl siding. I think I can easily remove the top row without causing any damage and in a way that it can easily be replaced.That’s where I’ll blow the insulation. The only thing that I wonder about is how much of the wall can I fill from the top. It seems to me that fire codes require fire stops to be inserted between all vertical studs. That means that I could blow the insulation from the top only as far the the fire stops. Anything fatally wrong here?
Some things should be left to licensed contractors. If you don’t know what you’re doing and don’t have a completely waterproof exterior sheathing system this could trap moisture in your wall and promote mold growth and wood rot. Before insulating a wall that was not designed to be, talk to a professional with experience with your era of home and the water proofing systems used. Walls are not waterproof, they redirect water. Make sure moisture is being managed properly or the $500 bucks you spent will turn your wall into a termite infested, rotting moldy wall that costs $20,000 dollars to replace.
Sorry, this is not a good example of how to blow in wall insulation, but way better this than no wall insulation. Cellulose can be dense packed, fiberglass is NOT better. The installers are crazy bad. Insulation dust everywhere. Huge holes. The hose is 4″ and reserved mostly for attic blow-in. Two holes per stud bay to allow for a better coverage. I can go on and on.
Sad thing is, for some of us, and I am one of those, we have very small jobs. For example, I have one exterior garage wall that runs the full length of the garage plus the area around the garage doors that need to be insulated. And that’s it. I can’t get a professional to come and give me a bid on the project because it usually falls under what they consider to be making it worth their time. The one company that came out looked at it said I fell about $350 below their minimum which is a thousand bucks so they won’t do it unless I give him a thousand dollars which for me is wasting about $350
“If you think hiring a professional is expensive, wait until you hire an amateur”… saying, kind of rings true in this example. That’s more like a 3-4 day job for a DIYer including research and fixing mistakes. Then a week of cleaning your entire house from fiberglass dust. Do what you do best then hire out the rest!
With the help of your article, plus the information provided by Home Depot on theirs (cellulose is my choice) I can see I will spend roughly $2,100 on insulation (R60) alone for roughly 3,000 sq/ft (excluding exterior cinder block walls) including attic, walls, and floor. The job most certainly looks easy. But certainly messy, and not suitable for pets to be in the area.
They forgot one very important thing. They did not restore the moisture barrier. In addition, fibreglass blown insulation has a terrible R-value to volume ratio. With the way your contractors did the insulation, all penetration areas have compromised moisture regions which over time will affect your dry wall as well promoting moisture wicking with your loose fibre glass insulation. For those perusal, Cellulose insulation is the best choice. Sorry 2 thumbs down on this job !!!
We drill the exterier? Just loosen A line of siding. Why did you do it from the interior? You could have avoided all that mud word. Nevermind just saw you had brick home. All the guys I work with have A chronic cough from this shit. I’d you’re doing A one off do it yourself it’s easy. Long term I wonder about health.
I have an old Stucco exterior house built in 1957 in a California hot climate that I want to insulate. In summer days, the interior walls radiate heat as I’m trying to cool it. I’ve read multiple articles advising NOT to blow in insulation. They say it can cause sick building syndrome, mold and dry rot in the walls “these houses were designed for the walls to breathe”. Any advice on how to cut down the interior wall heat?
Wouldn’t it just be easier to fill from the outside? Like pull off the siding from the top of where the wall is and cut the holes. Then putting it back together would be easier and you don’t have to worry about doing any drywall afterwords. I’d rather take apart some siding and reassemble that than dealing with drywall holes. Just my thought! Any people who do this for a living could you comment on this?
Materials cost of 25% might sound high it’s probably not really. When I was in the restaurant business 25% was close to our overall food cost. One item might have a higher food cost and another item might be lower but the overall average cost of the food we prepared and sold was close to 25% of what the customer paid.
You know it’s really stupid the guy should have started at the top and then what he needed to do was have another bit with it smaller so the air will come out and the insulation wount . Because what he did was he only cut half the wall so what he did was he only fill half a wall with insulation. If you had made a small bottom hole and put it at the top and filled it from the top go to the bottom it would have filled the whole wall so what they’re doing is they’re making you think they’re filling the whole wall but really you’re paying for the whole wall and you’re not getting the whole wall filled
I appreciate articles like this and have seen other articles using such a large house but this seems unsecary using such a large hose and messy… I was told by my local lowes store that all I had to do is drill 3/8 inch holes in wall like I’ve seen it done in the past on exterior walls and I know that has to be right as they sell 3/8″ plugs to cover holes afterwards.
Paper/cellulose settles up to 25%; pink stuff stays put but conducts more heat, so their negatives cancel each other out. Isn’t it time that we have an alternative to insulating/retrofit walls? And how is it that we don’t yet have a product that deters mice and other rodents? Mice treat this stuff like it’s cotton candy!
The wood behind the plugs is a bad idea. Your putting wood and screws BETWEEN your studs which means the next time you look for a stud with any finder, you wont know if you have a stud or one of your improvised and overcomplicated pieces of wood. So when you go to mount a tv or something heavy to the wall, you might just mount it to nothing without realizing it. Every wall in your house is now covered in obstacles to future work. You could have literally used tape and mud and been done in a fraction of the time.
Well, I don’t know why you keep complaining about what you paid for the insulation job that didn’t want to do. I dislike people like you that think that knows or thinks that they know everything. Moreover, I also believe I you hired those people to do that job because you didn’t want to get your girly hands dirty with fiberglass. I would suggest you that before you start making a article and complaining about how much you pay for a job, you should also do a research of how much the equipment that they use worth. And how much money does involve to do the job that you are hiring someone to do. you also tell your people that the insulation machine that those guys are using worth about $20k. I would like to see if you can get it rented at home depot/lowes or Sunbelt rental!