How to trim decking boards to leave a 12mm gap to house?

I have a deck where the boards are pressed right up against the house and I wish to create a gap of 12mm for drainage. I have tried using a multi-tool but it was laboriously slow and I don't want to lift the boards to make the cuts. Is there a power saw that can get close enough?

Thanks

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EricL

Hello @Phillipchin

Thank you for sharing your question about cutting your decking panels. Due to the space limitation you've imposed, I'm not aware of a tool that can get very close to the wall and allow you to cut such a tight channel. Since you are using a multi tool, I propose changing the blade to any of the following for a quick cut.

My best advice when using your multitool from the top and using a plunging motion, remember to swing the tool left to right Do not keep the tool and blade still, using the swinging motion helps the tool to cut faster and helps with removing sawdust in the cut. Please make sure to check compatibility and that the blade is suitable for your tool. It may take a while, but you will eventually be able to cut channel on your deck.

Please remember to wear personal protection such as gloves, goggles, ear protection and a mask when using your multi tool.

Let me call on our experienced members @Nailbag, @Dave-1 and @JoeAzza for their recommendations.

If you need further assistance, please let us know.

Eric

Nailbag

Hi @Phillipchin you will be there forever with a Multitool and will be cooking through the blades. But it will be the only tool that will get you that small 12mm off-cut. I would select high-quality wood only blades. They dont need to be anything more fancier as your not multi-material cutting. Get a plunge one if you have plunge cuts, otherwise that section of the blade isn't used. Multi-packs will be cheaper. Also make the cut a couple of mm short to allow you to clean up the edge of splinters. taping the cut line wont help when using a multitool in this application.

Nailbag

Noyade

"I have a deck where the boards are pressed right up against the house"

What is the wall type? How long a cut? Doesn't need to be pretty? (you're currently using a multitool).

Would you accept 15mm?

Dave-1

Good Morning @Phillipchin

Would you be able to give us a photo? I am trying to figure a way arround having to trip that much off. Depend if you are trying to stop water traveling down the wall to the boards or movement/expansion. I was thinking of a grinder with a timber disk but I think it would be a messey line to cut with against the wall.

If its water flowing down the wall then maybe an angled aluminium strip on the wall to kick the water off the wall. And a corrisponding piece on the top edge of the boards so the water dosnt roll back against the wall?

Dave

JoeAzza

Hi @Phillipchin , I had a look on line , I found these tools that might meet your request, it’s called a tow kick tool saw

The other is a Ryobi tool from Bunnings, you will need to check if it cuts close enough to the wall. Link below.

@EricL should be able to check for you🤞

https://youtu.be/OuT6Q9MtibQ

https://www.bunnings.com.au/ryobi-18v-one-multi-material-saw-r18mms-tool-only_p0249437

EricL

Hello @JoeAzza

I'm sorry but this tool is not a stocked item at the store. I can only suggest using the multi tool with the superior cutting blade.

Eric

MitchellMc

Hi @Phillipchin,

@JoeAzza might be on the money there with the Ryobi 18V ONE+ Multi-Material Saw R18MMS - Tool Only. I haven't been able to find any official specification, but through some investigation, it appears that the minimum cut width is 11mm (including the width of the saw blade) on this saw. So, with it riding hard up against the wall, you should be able to achieve your desired 12mm cut.

Mitchell

Noyade

"minimum cut width is 11mm"

I have been thoroughly beaten. 👍️

Mind you - if @Phillipchin's wall is brick - how would you protect the soft alloy left hand surfaces of the Ryobi?

MitchellMc

What did you make that cut with @Noyade?

Running some cloth tape along the bricks would likely prevent it from grinding away.

Mitchell

Phillipchin

Thanks everyone.

I bought the Ryobi Multi-Material Saw and it seems perfect though the bottom weatherboard may push it away an extra 2-3mm

JoeAzza

Hi @Phillipchin , Good to hear that you have resolved you issue, I was just about to suggest, the Ryobi and Ozito miulti saw

https://www.bunnings.com.au/ryobi-18v-one-multi-material-saw-r18mms-tool-only_p0249437

https://www.bunnings.com.au/ozito-pxc-18v-89mm-plunge-saw-pxpss-089-skin-only_p0540023

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