Avoid Problems When Spraying an Exterior

Updated May 9, 2024 | Posted Mar 7, 2021 | Professional insight, Miscellaneous | 1 comment

Hi, my name is Kris. I’ve been a decorator most of my working life and I just love exterior spraying. As a decorator, you can make some real money spraying substrates such as rough cast, or even smooth masonry.

That said, you can have a few issues too. In this blog I’m going to give you a few things to think about to help you avoid problems when spraying an exterior. I hope you find it useful.


Why should you use fungal wash before Spraying?


Yep, I’ve been there. I have applied masonry paint to old render without the use of fungicidal wash. Maybe you will get away with it, maybe you won’t. The paint finish can discolour or even fail on you. Why not avoid potencial problems all together and do your prep correctly.


Why should you only paint exteriors when conditions are perfect?


This one seems simple really. If you apply a coat of water-based paint and it rains before it dries, your paint will drip all over the driveway!! Or maybe you’re using oil-based paint and it goes cloudy because moisture has got to it. You might have adhesion issues because the substrate is wet, or your paint might not cure properly. You simply can’t expect the job to go right if the conditions aren’t perfect. Also, don’t be in a rush to start your exterior spraying season, or carry on too late in the year. Stick to the warmer months.

Using the right paint


This one should be obvious, but trade paint will always outperform retail. It’s no good trying to save a few quid on materials when the job won’t look as good when you’re done, won’t last as long, and you may experience problems on application. Why bother spray painting the exterior of your house if it will need redoing after a couple of years anyway?


Overspray on Next Door’s Car or Windows?


Yep, unfortunately I’ve been there too. It’s all about pressure! Make sure your gun is set to the optimum pressure to deliver the material, without over doing it. Spraying an exterior should be cleaner, with less overspray than if you were to use a brush and roller. If it isn’t, then you’re doing something wrong. Another tip is to always point your gun inwards when you come to external corners.


Trouble Shooting!! Problems and Solutions when spraying an exterior


No1. If you pull the trigger, but after a second or more you lose pressure and its spits material unevenly – Check the gauze/filter in the handle of the gun. The paint isn’t moving through your sprayer properly, so the chances are you need a new filter. If you have a sump feed gun (anti-gravity fed) check the filter if there is one on the intake.

No2 – You can’t get your sprayer to switch from prime to spray – Your actuated valve is clogged with paint. Take it out of the paint, fill a bucket up with water, take the tip off spray the gun so its just coming out of the pipe. Keep turning the switch back and forward from spray to prime, that should sort it. After it is free, turn the switch to “spray”, let the pressure build up, then turn it as quickly as you can to “prime”. This will dislodge anything that’s in the pipe. Repeat the process several times.

No3 – you’re getting lines of paint at the top and bottom of the fan when you’re spraying. Your tip is blocked. spin the tip round and blast any of the dried paint out the opposite hole of the spray tip. However, it could be that you aren’t getting enough pressure, in which case try changing your filter. The other possibility is your tip may be worn. In which case, you need a new one.


Protecting from Overspray When Spray Painting


The major drawback when spraying over brush and roller is you can’t cut in. That means you need to protect any doors, windows, downpipes and everything else you don’t intend to paint. Masking is the traditional (and best) way to do this. The problem is it takes an age to do. The time factor is a major problem for me as a decorator because time is money. So, the alternative is to use a spray shield.


I have used all kinds of spray shields in the past. In fact, I went on to develop my own, simply because nothing else on the market was up to the task. I’ll take you through the story of how my dad and me developed the Fox Spray Shield.

It was summer 2018. I was deep into the exterior spraying season. I mostly do exterior work, so I’m pretty good at the old spraying. I mask downpipes and use a spray shield for the rest. The spray shields on the market at that time where a bit naff to be honest. They were flimsy and started to rust after one use. I ended up having to buy a new one for every single exterior spray painting job I carried out. They just didn’t last!! They were like that wobble sheet Rolf Harris used to get down to tiny kangaroo with, can you tell what it is yet?

I knew there must be a better way, enter my father, 45 years as a contractor for the county council. He is currently living out his fantasy retirement making bespoke sheet metal body parts for classic cars.

I went to him with a quandary; can we make a paint shield that is rust proof, solid, sturdy and reliable? I went over to his workshop we had a few glasses of inspiration juice (Jägermeister, his favourite). We hit the drawing board. He quickly surmised that a double fold at the back would give it the structural integrity we needed. Materials, well, there was only really one option. Dad had some high grade aluminium kicking about, so we made one out of that. I’ll be honest, it was a rough prototype, but remember this was born out of an organic need. At the time we didn’t have envisions of a product. I just needed something to use to protect from overspray when spray painting.

Anyway, fast forward 6 months – the exterior season was over and we had done well. I didn’t know what to do next. What was the next move? late one Friday afternoon I popped into Crown Paints and I just so happened to have my crude aluminium spray shield under my arm. As I was cueing, the decorator behind me said “what’s that mate?” I explained I had made it to help with exterior spraying. He pounced, “can you make me one? I’ll buy one, how much?”

I went back to the van and thought nothing of it. Next time I was in that same Crown store and the manager said, “where did you get that thing you had last week? We have had people asking about it”

They put me in touch with Matt at Colemans, who are their sundry supplier. I knew we needed a better product. Everything we learnt from the first prototype was applied to a new design. The limitations of the first design were the length and size. We ended up going for a shield that would fit sideways inside a regulation size window and straight into a regulation size doorway.

Soon enough, one thing led to another and before we knew it, me and dad were in a meeting with the head of Colemans near London. This went well and we went to the Coventry painting and decorating show (2019) on the Coalman’s stand selling our shields. We got so much positive feedback we thought “maybe there’s something to this”. Then we had a chance meeting with the gentleman from 2decs1mic.

I reached out to them and they invited me for a pint. I give them a shield to try. They later invited me back to their studio to do a podcast. On the podcast we had a lot of fun and in hindsight I barely even mentioned the shield, but we had a great time. If you haven’t heard them, look them up. It’s a brilliant show for fellow decorators.

In the end of course, like everyone, we were impacted by the pandemic. I took a big step back from the shield and focussed all my attention on my painting businesses.

However, thanks to the Decorators Forum UK we had an influx of messages from people wanting the shield. I would like to take this time to apologise to those people I didn’t get back to in good time.

The paint shield changed the way I work, with a bit of skill pretty much anyone will reduce their plastic waste and material cost. We’ve all been there, bits of cardboard, plastic and all sorts.

I’ve still got the first prototype and I still use the first ever final product shield. We made sure we kept it clean and it looks as new as when it was made. Like my grandad used to say, when a tool is made right, if you look after it, it will look after you.

Put the cardboard and the plastic down, you’re better than that. You’re a professional and professionals need professional tools.



Updated May 9, 2024 | Posted Mar 7, 2021 | 1 comment

About the Author

About the Author

Mike Cupit has been in the decorating industry since 2002 and has mostly worked as a Trade Decorator in the domestic sector (peoples’ homes). Self-proclaimed “product geek”, Mike has a passion for paint and decorating tools. Mike now spends most of his time testing paint products and tools, comparing them to similar products on the market, and blogging about the industry in general.

1 Comment

  1. Przemyslaw Dankowski

    Very informative blog. Information is detailed in a comprehensive way regarding exterior spray issues. Insightful. Thank you for this.


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