Spray Foam Insulation Smell Bad? Here’s The Reason Why..

It goes without saying that the vast majority of Spray foam jobs are carried out without incident. However, in a few rare cases a pretty undesirably problem keeps rearing its noxious head.

This would be a pungent, fishy smell which has been reported to linger for a couple of months after installation, if the installer hasn’t managed to get to it first. The question is, how common is this and where exactly does it come from?

It can be hard to put a figure to how many Spray Foam jobs have problems, but it has been estimated to be less than 1%.

So most people who get foam insulation are not going to end up with an unpleasant smell which they cannot get out of their house. But why exactly does this happen? It’s time to find out…

Spray Foam Installation: The Secret Science Behind It

Fundamentally, spray foam insulation relies on two chemicals being sprayed into the wall and reacting together to form a nice, spongy foam which expands and fills the gaps.

However, this reaction doesn’t happen by magic, chemistry is a complicated thing and getting a chemical reaction to proceed can be very difficult.

Fortunately, a great deal of the work has already been done by the time the contractors arrive: The right concentrations of the two chemicals are present, a good mixing mechanism is already set up in the form of specialist equipment and a nice catalyst (a compound which gives the reaction a little boost) is mixed in.

However, a few more things are needed for the reaction to work properly.

Firstly, the reaction needs a certain amount of heat to start. As it is an exothermic reaction, namely the reaction gives out heat, it shouldn’t be too hot. However, without enough heat present the reaction will not start in the first place.

This means that you are going to be left with some of the chemicals sitting around in the wall.

Unusually for a reaction, the catalyst is ‘used’ in the reaction and, if the full reaction does not go ahead, some of the catalyst, which just happens to be a rather pungent amine compound, will also be sitting around in the walls.

Secondly, the two chemicals need to actually mix in the right quantities. If, for any reason too much of one is present, it’s just going to sit there left over and is never going to react. This also means that some of the catalyst may remain left over and just give off an unpleasant smell.

Spray Foam Off-Gassing: 2 Key Causes

So why would this happen? Well, fortunately for the spray foam industry, and unfortunately for the individual contractors, a lingering bad smell is, as far as we know, always the fault of the installer.

The two most common culprits are: spraying an inappropriate thickness into the walls, or spraying too quickly, letting the exothermic reaction get the next layer too hot to react properly.

Any time either of these happen, you’re going to get problems with the reaction go ahead properly, and the chemicals, the catalyst and the smell are going to remain.

Spray Foam Off-Gassing: What Can Be Done To Prevent It?

Will it stop smelling on its own? Probably, eventually. However, if you think about the amounts of ammonia catalyst that can potentially be sitting in the wall, how much is required to give off a smell, and how much is lost over time, it’s no surprise that the smell has been reported lingering for months or even years.

Unfortunately, if you’ve had a bad installation, it could be a very, very long waiting game. The only real solution is to take out the offending material.

However, the offending material can be very well hidden amongst all the foam which has been successfully installed, so it will likely be a case of taking most of the foam out, if not all of it just to be safe.

Fortunately, high quality, licensed professionals rarely cause this type of mistake and on the rare occasions in which they do, they’ll have to come and clear it up.

You’ve got more risk and more of a problem on your hands if canned spray foam starts to smell. However, as this is only suitable for small jobs, there shouldn’t be too much to scrape off.

Don’t dabble with installing spray foam yourself; get it right from the outset, by enlisting the help of the experts. Take the first step to creating a premium performing property today, by calling 0800 1700 636.