Concrete cutting (only very small piece. Possible?)

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Insanekiwi

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#304678 27-May-2023 20:08

Hello

I have a garage entrance which I would like to cut by something like 1.5cm x 3cm x by about 5m. It’s the lip of the garage entrance where the wheels hit as you enter. It’s hard to explain it but basically the garage door is currently sitting on the garage floor level and when there is a lot of rain it seems to let little bit through. If I can get the door to come down little lower but cutting a lip out - it should not let any water in. I think it’s a mistake by the builders.

Can a small thin layer can be cut tidily through the entire length of the garage entrance?

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#3080148 27-May-2023 20:50

Photo?

eracode

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#3080155 27-May-2023 21:11

Over the years I have cut quite a lot of concrete and concrete tiles and pavers with a Flexovit concrete blade in my Makita circular saw. Works OK - just need to be patient.

https://www.bunnings.co.nz/flexovit-230-x-3-2-x-22-2mm-masonry-cutting-wheel_p0502537?store=9470&gclid=EAIaIQobChMI3d6otZCV_wIVxnwqCh2EPA1kEAQYAiABEgKZqvD_BwE&gclsrc=aw.ds

Once I needed to cut an engineered-stone bench top. I hired a saw similar to the one below from Kennards (right now I can’t find the saw I used on the Kennards website). Had a 105 mm diamond blade. It had tubes to deliver water to the blade and workpiece - it connected to a garden hose with a standard Gardena-type hose fitting. The hose tap was set to deliver just a minimal flow - not full bore. This would work well in your case - probably better than the circular saw/Flexovit.

https://www.bunnings.co.nz/makita-1400w-wet-tile-cutter_p0204499

I also found this on the interwebs:

https://www.google.com/search?as_q=Circular+saw+concrete+blade&as_epq=&as_oq=&as_eq=&as_nlo=&as_nhi=&lr=&cr=&as_qdr=all&as_sitesearch=&as_occt=any&safe=images&as_filetype=&tbs=#fpstate=ive&vld=cid:5b025858,vid:3ppF_1hNvH0

IMO making the cut is not too difficult but you may have trouble getting the cut where you want it to go up close to the door frame at each end.

Doing it this way I think you will be making one long cut - then removing the unwanted piece with a Kango hammer - or by by laboriously going along and chipping it out by hand with a coal chisel and a lump hammer. If you were really keen you could make multiple parallel cuts to make the chipping-out easier and tidier.

Sometimes I just sit and think. Other times I just sit.

Dingbatt

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#3080160 27-May-2023 21:32

I know this is the DIY thread but…..

It might be worth getting a concrete grinding contractor to give you a quote for doing the rebate in the concrete that you are after. The reason being, it may be difficult to get a decent finish on the concrete you cut, which means you’ll have to either get a grinder and diy it. Or get a contractor in anyway.

I tried to do a diy cut and grind job to get a rebate for a side door we installed on our shed. Suffice to say the job ended up being covered by tiles to hide the bodgy bits! Mind you it was pre YouTube, so there was a lot more winging it involved.

“We’ve arranged a society based on science and technology, in which nobody understands anything about science technology. Carl Sagan 1996

Insanekiwi

592 posts

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#3080161 27-May-2023 21:36

Thank you all. I am going to get a professional as you mentioned. But I wonder if the horizontal cut (vertical cut seems easy as per the video!) can be done neatly and I want a sharp and tidy cut.

Vertical will have the depth control and just going straight. Horizontal cut will have nothing to lean against unless they have a specialised tools… or I guess their know how.

I will enquire and get back see how they do it!

eracode

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#3080163 27-May-2023 21:42

@Insanekiwi Might have been good if you had said in your OP that you were going to get a contractor in. It certainly sounded as if you were looking for advice on how to do it yourself - “… I would like to cut… “. And as pointed out previously, this is a DIY forum.

Sometimes I just sit and think. Other times I just sit.

Insanekiwi

592 posts

Ultimate Geek

#3080164 27-May-2023 21:44

Sorry! After reading your very thorough in depth reply - I decided this is no go zone for me! Don’t want to cause irreversible damage to my 3 year old garage!

hsvhel

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#3080166 27-May-2023 21:47

It sounds like you need drainage of some form

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SomeoneSomewhere

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#3080172 27-May-2023 22:15

hsvhel:

It sounds like you need drainage of some form

Not really - as I understand it, rain etc. hits the garage door, and runs down the outside of it. This is pretty much unavoidable.

When it gets to the bottom of the garage door, the garage door rests on the flat garage floor, so the rain running down the door hits the garage floor and forms a puddle. Some will go outside and drain down the drive, some comes back inside.

If you either a) slope the concrete where the door rests, or b) cut a recess so that there's a ~10mm step to inside, but no step to outside, then this puddle can only flow outside.

Getting this detail right is a bit tricky and requires actual competent contractors and planning, because the garage door is one of the last things to go in, while pouring the slab is one of the first.

Insanekiwi

592 posts

Ultimate Geek

#3080174 27-May-2023 22:19

Thanks. I do have drains right outside. Someone somewhere’s description is bang on. In Wellington with wind also blowing so hard doesn’t help that situation either.

I am looking at the garage floor sealing strip - I might this give a go first. It looks like it will do the job.

https://www.trademe.co.nz/home-living/outdoor-garden-conservatory/sheds-garages-storage/garages/auction-4142173043.htm

It suggests using butyl based glue - but can’t any glue that can be used outdoor work?

itxtme

2102 posts

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#3080177 27-May-2023 22:35

Since you will be driving over it you need something that adheres extremely well to the concrete so I would go with the butynol adhesive or it will have let go after driving over it 3 times. Just beware that you are creating a trip hazard with it. The Mitre10 ones have a paint strip to alert anyone walking in our out of the garage

SomeoneSomewhere

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#3080178 27-May-2023 23:01

OP is wanting to remove concrete, although I suppose building a lip on the inside could be an option too. As you say, adherence and longevity could be a major issue.

I don't think a 10mm rise on the vehicle entrance to a garage is sufficient to require marking.

nickb800

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#3080191 28-May-2023 07:17

Worth mentioning that you may need a garage door installer to adjust the door to sit lower after you've sorted out the cut. I strongly recommend you don't diy this part as the tensioning springs can be very dangerous

Ge0rge

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#3080200 28-May-2023 08:13

nickb800: Worth mentioning that you may need a garage door installer to adjust the door to sit lower after you've sorted out the cut. I strongly recommend you don't diy this part as the tensioning springs can be very dangerous

For 10mm, you don't need to adjust the springs. Just find the manual for the door opener and work out how to change the travel.

That's assuming it is a roller type door, not a tilt - and has an automatic opener.

I had this same issue when retrofitting a roller door to a pole shed. Instead of cutting out a chunk and trying to deal with a step, I just used the disc grinder to cut a v-slot the entire width of the opening, directly under the door seal. I then cut a series of evenly spaced slots at right angles to the door that lead to the front edge of the pad, as drain channels. Water runs down the door, capillary action sucks it under the seal, where it then runs into the v-slot and drains away. The slots are around 6mm wide, and about 5mm deep, the drain channels about 300mm apart.

Since doing this, I have not had any water come inside under the door - and that was from a good rain and wind pushing water about 500mm inside before.

Insanekiwi

592 posts

Ultimate Geek

#3080259 28-May-2023 09:31

(Finally getting to type on a keyboard!)

Love getting ideas off the clever folks on Geekzone. I was hoping that I could get away without adjusting the door with only about 1.5cm drop - it is a automatic sectional door; if it was tilt, then I will need a new garage door or a thick seal underneath afterwards.

I then thought about the adding a weather seal / strip - it seems to be around 1.2cm high; but like everyone else suggested here - how long will it stay and it’s not really a permanent solution. I don’t want to be fixing it every few months. Another issue - if you are cleaning the garage floor - you can’t just sweep the floor and will need to get it above the weather strip. This is an issue where Tesla produces quite a lot of condensation from AC (often they come on randomly) and I do occasional sweep the pool of water out the garage.

I am leaning back to the concrete cutting - will approach the garage door company to get advice about the height adjustment and see if they can achieve it cleanly.

Also will try to get a photo today and upload as it’s easier to visualise it…

Bung

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#3080265 28-May-2023 10:19

Insanekiwi:
I am leaning back to the concrete cutting - will approach the garage door company to get advice about the height adjustment and see if they can achieve it cleanly.

Concrete cutters are usually expert in fixing concrete placer's mistakes and omissions. There's one in Northland advertising "We specialise in the cutting of rebates for garage doors, windows and doorways. " . You just have to try your local area.

Most door openers seem to have progressed from limit screw adjustment to a learning mode to set upper and lower travel. Your handbook will have details. My sister-in-law has found that if the rubber seal isn't touching the ground your house will fill up with mice.

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