Spray Foam Insulation — The Ugly Truth?

🔻DIY Spray Foam Insulation ~ Is it a Good Idea?🔻

Roger explains the pros and cons of having spray foam insulation in your house.

Spray foam insulation explained by the Which? Team.

Also called spray polyurethane foam (SPF), it is an alternative to traditional building insulation.

It's versatile and can be used to insulate your roof, loft, walls and floor, helping to retain warmth and reduce energy costs.

PROS AND CONS

Spray foam insulation offers a number of benefits, such as:

✔ It can be applied in difficult-to-reach areas.

✔ In some cases, it can provide additional soundproofing.

However, there are also some significant drawbacks to consider, such as:

✖ It’s more expensive than other types of insulation.

✖ It needs to be installed by a professional.

✖ It can be difficult to remove once it's been installed.

✖ Potentially reduces ventilation within the roof space, causing humidity and dampness; placing roof timbers at risk of decay.

✖ Harmful fumes are given off during installation.

✖ It shouldn't be used in listed buildings or houses with thatched roofs.

✖ It’s often ugly, messy and can’t be decorated over.

✖ It can affect the value of your property.

✖ It may prevent buyers from getting a mortgage.

We'd strongly advise getting specialist advice from an expert or two in this area and proceeding with caution.

What is spray foam insulation?

Spray foam insulation is a liquid foam that is sprayed into position and sets into an insulating layer.

It can be used to insulate your roof, loft, walls, floors and more. It has been in use for more than 30 years and is now becoming increasingly popular as it’s an effective insulator and can also stop air leakage.

There are two types of spray foam insulation to choose from. Closed-cell spray foam Open-cell spray foam. If spray foam insulation is right for your home and budget, the type you choose will depend on what you want it to do.

If you’re looking to insulate your loft, the Which dedicated guide explains the different types of loft insulation.

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#SPF #FoamInsulation #RoofInsulation

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[Katyacat]

Some years ago we added a bathroom in our 180 year old brick farmhouse. When it came to insulation we decided on using spray foam. The chief reason for doing so was the number of rodents in the attic and walls. We were concerned about another space that the mice would have free reign at hence the foam. I did all the spraying myself. I used large kits that came with a 2 part foam in 2 pressurized tanks of chemicals. I suited up in coveralls, gloves, hood, face shield and HALF FACE respirator. The spraying went quite well using 2 kits to complete the job. when I got to the end of the first kit of tanks it spewed gases out without any foam forming. I completed the job with a second kit. To my surprise the house was filled with a fog. Well as it turned out it was only in my corneas. With a trip to the ER I came home with foggy vision and told by the ER doctor to seek specialist help in the morning. To my delight the fog had disappeared and my vision restored. So my advice is to let professionals do the work or use FULL FACE respirators.

[climbingsticky]

I work as a carpenter. It scares me how willing we are to fill homes with plastic. This is going to be a recycling and waste nightmare in the future. I hate how much waste building homes produces. Mircoplastics into the environment just from cutting kingspan (no i'm not talking about proper dust extraction on site, where do you think the dust bag goes) let alone dealing with the waste of re-roofing later on down the line. Roger I respect your building skills and knowledge and have learnt a lot from Robin and yourself. What can we do to change the industry for the better?

[iketheranter]

I worked for the man that invented this product. I'm glad you detailed the many possible drawbacks with this material. I was in the manufacturing side but was also required to understand the different applications which required different product mixes.
Personally I have always had concerns with long term degradation and off gassing. Everything breaks down over time.
Also, moisture build up or leaks can be a real problem. Running wires or piping after the initial construction is also a problem.
I think you covered it all quite well.
Btw, this material was discovered by accident. The company was called Flexible Products which specialized in flexable adhesives. The inventor and his brother were experimenting with a new formula for quite a while looking for a stronger, construction type adhesive. One morning they came back after a late night in the lab of what they thought was a failure and this huge foam blob was covering the table they had been using.
Years later, he sold out to DOW chemical and generously paid his long term employees large severance/ profit sharing checks and he retired.
Unfortunately, a short few months later, he passed away at a golf course on Tybee Island.
He was a good, kind, generous man and everytime I see this product, I think about him.
Thanks for your time.

[KurtBendl]

I had spray foam professionally done after a rehab of a 115 year old home. I gutted the attic “apartment”, repaired the weighted window pulls, ran all the electrical and CAT-6, added a proper adjustable vent, then spray foam in the rafters and walls up there, drywall, carpet. It went from the most uncomfortable room in the house to where the kids and I spent most of our time. Also sprayed a barrier around the skirt of the house which was exposed and accessible above the sandstone blocks in the basement. This house is in the southeastern US, where it’s hot and miserable in the summers, and grey and damp in the winters. Spray foam is _the_ best investment in energy savings and comfort I’ve ever made!

[pauldaignault]

I got spray foam installed in my new home ten years ago. It was the open cell type. It’s been great as my utility bills are lower and the house is quiet. Cost was $7000 more than regular blown in cellulose insulation..it has paid for itself and will be a selling point when I come to sell the house. Absolutely no bugs in the house as it is completely sealed. I would do it again with another house.

[gwil]

As an electrician I also always see issues where original cabling hasn’t been designed to surrounded by that extend of thermal insulation, which can lead to over heating of cables and possibly fire.
Also I see it as a nightmare situation if you ever need to make a repair or alteration, to locate or even cut through all the foam to add cabling for new fixtures or fittings.
Personally I believe that of this kind of insulation os going to be used all services should be informed so that it can be taken into consideration during design so that cabling size and maybe a conduit system could be installed to address certain potential issues. All this just means greater cost elsewhere so for me I would always go for modular insulation.

[dugbert]

Almost 30 years ago we spray foamed the slate roof of an old stone cottage (inside obviously). This was done directly to the slates. I was worried for a long time about what we had done but here we are 30 years later and it's been absolutely faultless. We haven't even lost a slate off the roof in all that time. Not one. The main roof timbers were left exposed for the cottage look and the foam was hidden with plasterboard so, to the casual observer, it looks like an original ceiling. The cottage is very warm too.

[HairyKnees]

I live in a very cold area (below freezing for many months at a time) and spray foam is very popular due to eliminating drafty gaps. It’s good in new builds with the correct ventilation system for it. Mortgage companies in my country are fine with spray foam, so that must vary by country.

[kirk]

I was a deputy fire chief in my city in South Louisiana (USA). The highest Carbon Monoxide Level issue I had ever come across, was in a renovation house. The house was elevated on piers (about 18", common practice in wet Louisiana), new windows, new doors, spay foam, new sheet rock. Furnace and water heater were not replaced. Fortunately the owners had an alarm system that included a CO detector and the alarm company made contact with the FD. The reading was over 225 ppm on our meter (33 ppm over 8 hours sets an alarm for work environment). Fortunately, no long term effects were had by the occupants. The occupants said "everything was new, had to be a faulty detector". After investigation, it was determined that the renovations were done so well, that a house that was designed, and needed to breath, no longer could. The house was initially built in the mid 1800s. This incident has always stuck in my head, and will never add such measures in a renovation. Just my 2 cents.

[gordonbruce]

A well balanced presentation Roger, the biggest issue in our opinion, is when something does go wrong !! it is a nightmare to locate and assess the full extent.

[garyredmond]

"A professional coming in and spraying the inside of your loft...."

Very optimistic there Roger with the use of the word 'professional'.

[pauldaignault]

I had spray foam installed when I had the house built ten years ago. I was aware that a roof leak could compound things a bit as the foam could retain some moisture. To add an extra measure of protection I specified that a premium quality synthetic roof underpayment be used instead of tar paper. I went with Titanium UDL-30. That’s the sort of thing that is used in Miami where hurricanes are common. This stuff is head and shoulders better than tar paper, but it costs the same price. You might lose all of your shingles in a storm, but your roof still won’t leak. It also does not tear or decay like tar paper. Having done that I did not have to worry about a roof leak with foam installed in my roof. I should also mention that with foam installed in your roof your entire attic space will only be about five degrees cooler or warmer than the ambient air in your home’s living space. That reduces the strain on your hearing and AC system located in your attic space.

[hebgilo]

I used closed cell in my exterior walls, then batt behind it. Low utility bills. 28 years later still no issues. I'll use it again in my next house.

[jackuzi]

I bought a house that had a sort of sunroom put on as an addition, over a crawlspace. I wanted to convert it into living space by adding a minisplit heat pump, but the floor was cold and drafty. Spraying foam on the underside of the floor solved both problems, keeping it warmer and sealing out all the drafts. I bought a tank of foam spray and it worked very well. You must wear eye protection and have very good ventilation--I had a box fan running on its highest setting blowing in from the entrance of the crawl space the whole time--there's no such thing as too much fresh air.

[rodney]

We have closed cell foam insulation in our 2200 sq ft two story home. We have Anderson 400 series window with tinted glass. Our house was designed and built to be air tight. The HVAC contractor studied the plants and in concert with the architect they designed a system that includes fresh air make up system that tempers the incoming air by using the exhaust air. All of the parts and materials were available and none had to be “special” ordered of fabricated. Having worked in the home construction industry for most of my life, I believe that spray foam is the best bang for your buck if you look at the entire house holistically and systems vs individual pieces of the system. We heat with natural gas and have central air. We live in the northeast U.S. and we have never paid over $100 per month for our gas and or electric service. While we paid more to build the home, our ROI is occurring within the first six years of our completed date. Thank you.

[robk]

This must be a UK issue. No mortgage company in the USA ever asks about spray foam.

[aquatus]

I actually experienced an unexpected bathroom issue, where after spray foam, the bathroom began to stink of sewer gas. It turned out that the seal in the house was so good, the vacuum effect you spoke about was in effect, but the bathroom fan was a bit overpowered and it would actually suck an occasional bubble out of the water trap in the toilet whenever the bathroom door was closed. We actually had to keep the bathroom door open to prevent that until we got a less powerful fan.

[largelarry]

I made walk in freezers and coolers for years and we never had any sort of water problems. In fact, the water would run off plus the foam was so tight on the metal skin there was no room for water. People also overlook how strong the foam is, having it inside a wall would make it much stronger than fiberglass in the same wall. If you had two walls one with spray in foam and one without, I bet the foam wall could support twice the weight. It's not all bad you just need to let it off-gas before covering it up.

[martinmorgan]

Roger, I always enjoy your videos, which are packed with information that the normal home owner would know nothing about.
You touch on the matter of the condition of roof rafters that could become saturated if roofing felt breaks down, and it's that which would steer me towards using Celotex or similar.
Now that you've told your viewers how YOU create a warm roof, that's a 100% steer for me!
Thank you. Keep up the good work!

[kenbeiser]

As I said elsewhere, I have about 30 years experience as a timber framer using with SIPs and closed cell polyisocyanurate spray foam insulation systems. I am retired now but I lean more towards dense pack cellulose without an air or vapor barrier/retarder. Finding “craftsman” willing to do it my way is difficult. I am fortunate to have satisfied clients that let me observe what works (and what doesn’t). Some places had blower door tests and thermal imaging to help me monitor our quality control.

So at 66 my wife and I are going to do dense pack cellulose for my “last” place …..ourselves.