How to water-seal edges of an Absco garden shed?

Hello @bennyboy

Welcome to the Bunnings Workshop community. It's fantastic to have you join us, and thank you for sharing your question about sealing the edges of your Absco shed.

I suggest having a quick look at this discussion - How to seal the bottom of shed walls? by @jjebw. The product my colleague suggested is the Sikaflex 11FC, you can also use Selleys 290ml Grey Storm Waterproof Gutter And Roof Sealant as an alternative. My only recommendation before using the sealants is to give the area a really good clean with a blower so that there will be no dust and debris when applying the sealant.

If you need further assistance, please let us know.

Eric

Hi @EricL fantastic advice there, another great method is to sikaflex down aluminium right angle inside this forms an inside wall against water along with the sikaflex.

Hi @CSParnell

That's an excellent recommendation, let me tag @bennyboy to make sure they see your suggestion as well.

Eric

Thanks a lot, Eric. I really appreciate the responses provided.

I'm leaning towards using the Selleys sealant, seeing how it can be applied in the wet as well.

Hi mate, thanks for your suggestion. I didn't understand how to go about this though. Please could you elaborate a bit?

Thanks in advance, and I really appreciate you taking the time to help me with this request.

Hello @bennyboy

Let me tag @CSParnell to make him aware of your question. Please just keep in mind that not only do you need to seal the bottom edge of the shed, the gaps where the panels sit in the "U" channel need to be sealed both inside and outside to prevent water from coming in.

If you need further assistance, please let us know.

Eric

Hey @bennyboy,

What you are doing is installing a lipped barrier internally to your shed with the use of the ally angle.

I suggest using the sausage polyurethane as its better bang for your buck, you want to apply a seal to the bottom edge if the shed and depending on how much water is actually coming in you might want to seal in the channels as well but this will use a lot more polyurethane. The apply a line of sealant to the top half of the ali right angle and the underside if required if not enough spill over from sealing bottom of shed and stick the ali down so it forms an internal lip.

Why I say if you require to seal in the channels that if you get down pours and water is likely to rise hight than 25mm of the lip of the ali channel?

So here is the products to use.

Screenshot_20220902-161403_Bunnings Product Finder.jpg

Screenshot_20220902-161538_Bunnings Product Finder.jpg

Screenshot_20220902-161645_Bunnings Product Finder.jpg

Thanks a lot @CSParnell and @EricL .

I've gone ahead and bought Sikaflex as per the initial recommendation, along with the caulking gun, and will give your recommendations a try.

I don't believe there is a large ingress of water, so a bit undecided on installing the aluminium angle as an additional barrier yet.. however will update if this is not the case.

Thanks once again. Shall update once I have results.

No problems @bennyboy see how u go as you said you can always add afterwards if required. Make sure the concrete is nice and clean and free from dust prior.

Let us know how you go.

@CSParnell @EricL Here's a quick update.

I had a look this morning, and can see what is the possible cause of the water ingress.

Gap below frame

Sealant applied

Sealant appliedSealant applied

I suppose I shall consider sealing the channels following results from the next rain, as that would require a LOT of sealant. 🙂

Remarka6le

Hey @bennyboy ,

I installed a similar yet smaller shed when we first purchased our house, it's great that you've done this as soon as you've built it so as to not be impeded by anything, but if I could do things again, I'd have sealed the channels right from the start. Trust me when I say it is worth the extra effort and sealant, you also wouldn't have to clean out as much gunk (and other various things) if you did it from day 1. Loving the results btw 🙂

Great work that should definitely keep it at bay.

Hello @bennyboy

Thank you very much for posting those photo updates of your shed. It looks very well sealed, I think that should be sufficient to keep your floor dry.

Eric

Tagging @EricL and @CSParnell for their attention.

We had some good rain this morning, which was a good test for the sealant work i had done over the week at the inner bottom edges of the shed.

Most of it has held well, with the only signs of dampness being around the anchor bolts in the concrete, which makes sense as there was no sealant around the region where this meets the shed edge. Probably not a major issue in the grand scheme of things.

Dampness around the anchor bolts

However, where I'm facing an issue is the water ingress from the region around the doors. I suppose the design of the doors doesn't do enough to prevent the water collecting at the bottom of the door channels and making its way into the shed, overriding the sealant applied to the bottom of the door jambs. 🙁 I also suppose the gap below the door may also allow for water to make its way in to the front of the shed.

Open to suggestions from the folks here.

Water ingress at the front of the shed

Remarka6le

@bennyboy A small guttering system on the front section of the shed may work? I know member pstq did something similar with his shed and that seemed to work.

@Remarka6le , what a find.. that is the exact same shed model!

Certainly does look like a design oversight, more of an issue if your shed front tends to get a fair copping of rain.

I don't reckon i have the skills to chop the door height as done by pstq, so need to see what other ways are possible to resolve this.

MitchellMc

Hi @bennyboy,

We'll need to determine exactly how the water gets inside to devise a solution. Does it appear that the rain is running down the outside of the door, filling the bottom channel of the door frame and then flowing over the back of it and inside? Those bottom door channels have a higher and lower side. The lower side goes to the exterior, allowing the filled water to go outside instead of inside the shed.

There should be a 20mm overhang that will allow water to escape the C channel roof capping without running down the wall. It sounds like the roof might be misaligned, causing the roof sheeting capping to touch the front walls capping. Have a check to see how much roof overhang you have on the back of the shed. The roof is misaligned if there is more overhang on the back than the front. There should be around 20mm on either side. If the roof capping touches the wall, water will run through the top of the wall or doors. If the roof ridge beam was installed off-centre, then the roof sheets will be too, causing this misalignment. You'll need to shift the ridge beam and sheeting into the correct position to stop the water ingress.

Failing to identify the issue, if there is a big enough gap under the door, I'd suggest pop-riveting an L profile onto the bottom frame would help immensely. That way, anything that runs down the door should be pushed back outside by the profile. I've created the below image to illustrate.

Please let me know if you have any questions.

Mitchell

@MitchellMc thanks a lot for your reply and taking the effort to illustrate the same.

I had a look at the door channels, and they are indeed high side outside, which as you mentioned is incorrect. I do remember doing it this way just for doors, but went back to check the video from Absco to see if this was mentioned there, and no, it isnt. I'll have to swap these the other way for sure, as you mentioned.

In addition, i also checked the alignment of the rood capping to the front wall capping, and it does look like they touch, which could explain the ingress/flow from here, I will need to double check this once again when it rains, to confirm this is what's happening. 🙁

I believe the L profile installation will be a good option once i have checked out the other suspects as above.

Thanks once again for your help.

Hi @bennyboy

It's a solution worth exploring, if the gap can be covered with the "L" profile channel then there will be no need to attach anything else to the shed.

Please keep us in the loop, we look forward to hearing the results.

Eric

@bennyboy good to see you have the bodyboard ready to go though 😉.

Don't forget you can check with a hose running water on the roof and across the roof and on the doors for controlled flow to try to track it down.

@s but your almost there keep going.

Carl

Hi Ben I have the same issue with water entering under door. I have sealed the entire inside base with Sikaflex. How did you solve your issue

Hello @jbellerby,

Welcome to the Bunnings Workshop community. Thank you for joining the discussion.

Our last recommendation about the leaking door was to put in an aluminium angle at bottom of the frame so that the door would sit on it and any rain that came in would be guided out at the bottom. Let me tag @bennyboy to make them aware of your question.

If you need further assistance, please let us know.

Eric

Thank you Eric. Do you have a photo? And what size angle?

Just trying to workout how the angle works with the bottom door latch. can you still open second door

Hi mate, I still have the issue as I didnt get around to implementing any of the final suggestions provided by EricL and the team.

This is after the rains we had in Brisbane this morning.

March 2023.jpg

I believe in addition to the issue with just the water making its way in from around the door, there is also the fact that concrete being porous absorbs the water falling on it, and manifests itself as wet surface as seen here. This means that even if there is no water physically entering, the rain water which is draining out via the channels on the bottom edges seep into the concrete and show up as being wet. Please correct me if wrong.

Hello @jbellerby

If you go back to the second page of this discussion, you'll see an excellent render and an explanation by @MitchellMc. The angle piece he was referring to was the Metal Mate 25 x 12 x 1.6mm 3m Aluminium Unequal Angle. I'll re-post the image below.

If you need further assistance, please let us know.

Eric

Thank you I have fitted a piece

Hi Eric what size rivits should be used. Not sure of the thickness of bottom rail. Angle is 1.6mm thick thank you

MitchellMc

Hi @jbellerby,

Otter 4.0 x 4.8mm Open Aluminium Blind Rivets should be in the right ballpark. They have a grip of 4.8mm, so it gives you 1.6mm for your angle and 3.2mm to capture the bottom rail. I can't imagine the rail would be that thick, but the rivets should still grip solidly if it's thinner.

Please let me know if you have any questions.

Mitchell