Best waterproof garden shed floor? Thoughts on Pavelock?

I want to make my new garden shed floor as watertight as possible. My other garden shed was installed on concrete pavers 3cm thick, but water keeps seeping into the shed inside wetting things in there. It was professionally installed and I believe they bolted it down and then sealed it around the inside edges in places with a regular sealant, but it doesn't appear to have been enough to keep the water out which is very frustrating and literally a waste of my money.

So I would like some advice on my second shed floor. I can't have a concrete slab so that really only leaves concrete pavers again. I am wondering if it would be okay to lay the concrete pavers then put a steel frame over them and then some sort of floor over the steel frame so that the shed is raised off the ground. What does anyone think of that method?

The person who is going to install the shed said it was overkill and all it needed was to lay the concrete pavers and then seal them with pavelock to make them watertight, and then once the shed is installed then put a sealant around the edges inside. I'm not sure about this method as I have no experience with pavelock, but as someone who is anti pesticide and anti chemical I am worried that it's very toxic and the poisons could leach out eventually which could be inhaled by anyone near the shed.

Thank you for any advice.

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Comments

Akanksha

Hello @Minty,

Many thanks for your question on waterproofing your new shed floor. I'm sure our resident D.I.Y. expert @EricL will be happy to assist and provide his thoughts around Pavelock and other methods when he's back online later today.

If possible, are you able to provide any photos of where the shed is going to be installed or any other relevant photos? This may help our members get a better idea of what you're working with and allow them to provide more tailored advice.

While waiting, I also encourage you to have a read of our step-by-step guide How to waterproof a shed floor in case it helps. You may also find the following discussions useful:

Akanksha

EricL

Hello @Minty

Thanks for sharing your question about having waterproof flooring for your shed. Since you are not keen on having a concrete slab on the soil, I suggest building a timber frame on DEKO 250 x 150 x 150mm Instant Concrete Foundation Block. These blocks are easy to use and can easily be moved if you need to change position.

Since the shed flooring is above the soil it will prevent any rainwater or moisture from settling in the shed floor. As for the floor itself, I suggest using 2440 x 1220mm 12mm Plywood Hardwood Marine AA Grade If you are looking for further protection you can line the inside flooring area of your shed with BGC Fibre Cement 2450 x 1200 x 9mm Durascape Fibre Cement Sheet.

I've sketched up a sample frame to give you an idea of what the flooring can look like. I also suggest having a quick look at these guides - How to build a Low-level deck by @Adam_W and How to Build A Deck by @MitchellMc.

If you have any other questions we can help with, please let us know.

Eric

Minty

https://www.workshop.bunnings.com.au/discussion/comment/28955#Comment_28955

Hi Akanksha, thanks so much for the links to the articles and step by step guide, appreciate it very much.

Minty

https://www.workshop.bunnings.com.au/discussion/comment/28967#Comment_28967

Hi Eric, thanks so much for taking the time to explain this shed flooring option for me, and the diagram is really helpful. It's along the lines of what I was thinking but wasn't sure what materials exactly were needed. So I really appreciate the pictorial to assist me in that. Also the links to the articles as well which will be helpful to read.

Just one question, will this flooring method be suitable for a 3m x 1.5m shed?

Minty

https://www.workshop.bunnings.com.au/discussion/comment/28967#Comment_28967

The weeded area is the proposed site for the 3m x 1.5m shed in my backyard. There is 900mm distance from the house wall.Hi Eric, just had another question if that's okay.

The person who is installing my shed (who is a Bunnings shed installer) has said that I don't need to bother with all of that fuss with things like the Decko blocks, frame etc. He said that all I need for the shed floor are concrete pavers with pavelock which will 100% keep any water, weeds, etc, out.

Is this correct?

Also, if I have to take the option of using concrete pavers for the shed floor, can I use them without pavelock and then just use a sealant such as Sikaflex 11FC which I saw recommended on another post here? Or would you recommend something else?

In the latter situation which would be the best type and size and thickness of concrete pavers for a 3m x 1.5m shed, to give it the best chance of being as watertight as possible?

Thank you.

EricL

https://www.workshop.bunnings.com.au/discussion/comment/77040#Comment_77040

Hello @Minty

Thanks for the additional information and the picture of the proposed site. Pavers being a porous material often hold moisture inside of them. When the temperature is cold enough it causes condensation on the surface of the paver. To add an extra layer of protection against moisture, I recommend putting in builder's plastic on the ground and then put the pavers on top of the plastic. The plastic will serve as a moisture barrier to prevent ground moisture from passing through the gaps of the pavers.

The Sikaflex 11FC will provide an adequate seal between the pavers and keep them together. The adhesive is stronger than Pavelock and it will last much longer even with vigorous cleaning of the shed floor.

It all depends on your budget and how much protection you want to give your items in the shed. I still believe that the elevated frame would give you better protection. One extra plus in having an elevated frame is that even if there is a large deluge of rain or a severe thunderstorm, your shed floor will be high and dry.

In regards to the type of paver, I propose getting something that is at least 40mm thick so that it can carry some weight. I also recommend getting the biggest one at the most affordable price so that that there are fewer gaps. A good example would be the Custom Concrete Products 600 x 600 x 40mm Plain Paver.

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

If you need further assistance, please let me know.

Eric

Noyade

https://www.workshop.bunnings.com.au/discussion/comment/102486#Comment_102486

Evening @Minty

"3m x 1.5m shed"

Sounds like a pathway? Only 1.5 metres wide?

Do you have access to a concrete mixer?

I'm thinking you make a small concrete slab.

Dave-1

https://www.workshop.bunnings.com.au/discussion/comment/77040#Comment_77040

Good evening @Minty

I would also be concerned about water into my shed. All the sheds I have seen built at ground level end up having water run through them. Both bconcrete flooring and paving ones. I like @EricL's idea as being the most dry long term.

If money was an issue you could still have a raised floor using pavers or bricks to rest the timber on. I like the idea of a raised floor for air circulation and ease that water can run away. With pavers even with the plastic barrier underneath water can still come in from the top. What type of shed are you going to have? Is it a premade that is put together?

Looking at your picture one question is where will the water go when it rains, wether you use pavers or raised its always an idea to follow the path of last resistance with water.

Dave

Minty

https://www.workshop.bunnings.com.au/discussion/comment/118251#Comment_118251

Hi Noyade

Yes its definitely 1.52m depth x 3m wide.

No, its not a pathway lol.

No I don't have access to a concrete mixer but thank you for your suggestion though, many people have suggested a concrete slab to me as well! Unfortunately its not an option for me.

Regards.

Minty

https://www.workshop.bunnings.com.au/discussion/comment/102487#Comment_102487

Hi Dave-1

Thanks for your feedback, much appreciated!

I agree too, I don't want concrete pavers for my shed floor, I would like something raised as my first shed that was installed professionally by a shed company used concrete pavers and water keeps getting into the shed everywhere and soaking everything in there which is really upsetting as it all cost alot of money and now it is virtually unusable.

Hence, why I am trying to use a different type flooring for my second shed. But the installer I am going to use said its not necessary to use raised floors, he says all I need to do to make it watertight is to use concrete pavers and then seal them with Pavelock. He is also not going to use a plastic barrier underneath as he says that it is not necessary either. He said he is just going to put sand down on the ground then the concrete pavers on top of the sand, and then seal the pavers watertight with Pavelock which he said absolutely nothing can get through. But I don't want to go down that route for obvious reasons already mentioned even if this Pavelock product is the bees knees.

The shed is an Absco Premier double door 3m x 1.52m, bought from Bunnings. It's flatpack and has to be put together. I don't know of any sheds that are premade, if I did I definitely would have bought one!

I will suggest to the installer again about building the shed floor as per Eric's idea or even your idea of putting a timber frame over the pavers to raise the floor that way. I don't know how much a shed floor would be if I went with Eric's idea or your idea. All I know is that if I use the concrete pavers which Eric suggested but nothing else then I need about 15 or 16 of them for my shed size, and I think they are about $28 per slab which really adds up to be quite expensive anyway.

I actually don't know where the water would run off to. To the north of the shed site (which is out of view in the picture) there are two steps down into my carport, so maybe the water will run off there. Or maybe its not a good site for a shed and I should rethink it altogether?

Thanks again for your suggestions.

Regards.

Minty

https://www.workshop.bunnings.com.au/discussion/comment/102486#Comment_102486

Hi Eric,

Thanks for replying back, I really appreciate it.

Thanks also for the diagram, that is so helpful!

I completely agree with you about the pavers for a shed floor and the problems they can encounter. I don't want them at all but the person who is going to install the shed said that he won't put in any other type of shed floor other than the concrete pavers, because he said it isn't necessary. He advised that the concrete pavers will be perfectly fine on their own and that they will be watertight with the pavelock applied to them. He also said that he won't be laying down builders plastic under the pavers either as he said that it is a waste of time and unnecessary. He advised that his method is going to be to apply some sand directly to the ground and then lay the pavers on top and then seal them with pavelock and that's it. I'm unhappy about this though and have told him so several times. Whilst I respect his opinion and his right to use any method he chooses, maybe I just need to find a new installer who will be on the same page as me about the shed floor. Only thing is I have already paid the money to Airtasker to use him (although he told me that he is a registered Bunnings shed installer too).

Thanks for the advice on the Sikaflex 11FC. I did see that it was recommended several times on another Bunnings Workshop page and I had intended to get it if I do have to use pavers, but I didn't know it was stronger than the Pavelock so thank you so much for pointing that out. Not sure why the shed installer for this shed didn't know that.

I definitely want to have an elevated floor as I want as much protection for my things inside as possible, due to the water seepage issues I have experienced with my other shed due to the installers installing the shed on basic 3cm thick concrete pavers and nothing else. Total waste of money and ruined my things. However, I don't know how much it would cost in total to have a raised floor. I did look at the links you provided earlier for the Decko blocks, etc, I'm just not sure how much it would all come to for my size shed as its way over my head to do those sorts of calculations.

In regards to price comparison between pavers and elevated floor materials, I'm not able to make the calculations as the link you provided above for the pavers is broken and doesn't work (I googled the product on another page and it says that the product is not available in my state in WA.....so not sure if that is why it says the link is broken). So I don't know how much 15 or 16 of those pavers would be (which is the amount I think I need for my size shed) and I don't know how much a raised floor my shed size would be either as its too difficult to work out.

Regards.

TedBear

Hi @Minty, I have found that with many small garden sheds that the internal floor size fits slabs neatly inside the frame. My method in those cases has been to put the shed onto a foundation base of either 1/2 slabs or a row of bricks (Just around the edges - underneath the frame itself). Then fill the inner area level with sand. This gets the frame a bit above ground level. Then I lay plastic (edges turned upward into the shed) and then lay the slabs sitting inside the frame, such that the floor top, where items sit, is then above the frame bottom and above where any water could get in. The weight of the slabs which sit on the frame lip also helps to hold the shed down in the wind. Should any water (runoff from the walls) get under the shed it doesn't matter much as it would have to go upwards through a layer of plastic sheet and a layer of slabs (or whatever you use) to get to the stored items. Maybe that's an option for your situation? It could potentially work using pave lock instead of slabs. (Said without seeing the actual job.)

MitchellMc

https://www.workshop.bunnings.com.au/discussion/comment/118254#Comment_118254

Hi @Minty,

The basic principles to a shed not leaking are the base needs to be elevated above the surrounding ground, and the shed's footprint must match the shed base exactly. The reason for elevation is so surface water on the surrounding ground can't flow straight into the shed. The reason the footprints need to match is so rain can't fall on the surrounding base and flow into the shed. Typically a slab is created that is slightly larger than the shed's base. On the edges of the slab that might be exposed, they are rebated so any rain that hits them flows off away from the shed.

I'm happy with the slabs raising the shed above the surrounding area, but they'll still become saturated in heavy rain and wick moisture inside the shed. Adding a plastic underlay likely won't resolve the issue. If you were going to use slabs, I'd recommend you then raise the internal floor by following this guide: How to install a shed floor. Those materials would cost around $300 to raise the internal floor.

Please let me know if you have any questions.

Mitchell

Dave-1

https://www.workshop.bunnings.com.au/discussion/comment/118254#Comment_118254

Good morning @Minty

Have been thinking of your issue over the weekend. (As you do lol)

Just looked up air tasker to see what happens if you cancel a job (You get your money back as air tasker credits if they accept it)

I suppose you can see the path I am heading along with the above line. Surely the installer has to do what the owner wants? Even if they dont want to you are the one paying for it. Maybe you can cancel and try again with another installer? I had a look at the install video and man it sold me on how easy the shed can clip together.

Hope I am not adding to the stress of choosing. Have you decided on what you would like for a floor? The last part I coulkd suggest is that Bunnings do have a list of installers. Might be worthwhile to talk to Bunnings and see what one of them may cost compared to airtasker.?

Dave

Minty

https://www.workshop.bunnings.com.au/discussion/comment/127523#Comment_127523

Hi Dave-1

Thanks so much for your further feedback on this, I really do appreciate it. I haven't had a chance to reply back to any of the responses yet although I did manage to read them all and have been considering them over the weekend, as each has given me something meaningful to consider including yours.

No you are definitely not adding to the stress of choosing at all! The stress was already there and was only getting worse if I didn't try and reach out and get some opinions and ideas. It has been alot to consider but also necessary as I need to make a decision at some point soon because that shed isn't going to build itself lol.

That's really kind of you to look up Airtasker's policy on cancellations, I really appreciate that. It's my understanding that if I cancel the job with Airtasker that as you say they will only credit the money back to Airtasker and not to me. So that if I do find another installer it will have to be through Airtasker as the money cannot be used elsewhere.

I have decided to go with Eric's suggestion of using the Deko blocks with a frame on top and then a floor on top of the frame, which is along the lines of what I had envisioned in my mind when I originally set out on this journey into the world of shed floors and installations. I reached out to the installer again yesterday and advised him of this yet again, and implored him to respect my choices and opinions on what I want for a shed floor. But it didn't really go down too well which is just further adding to my stress of what to do, because he has refuted everything that I want which has been recommended to me on here.

He said that Bunnings don't do site work so they are incorrect on their advice to me about putting builders plastic under concrete pavers. He said that if you put plastic under paving then at some point it creates moisture because the pavers can't breath in certain weather conditions, so you get an odour in the shed like an old house. He also said that you can't use Sikaflex 11FC to seal the shed floor either as the floor needs to breathe. So its all a little puzzling. But personally I've always found Bunnings to be an immense source of accurate help and advice which has always been correct, so I am quite puzzled at his responses particularly as he is a Bunnings installer.

You mention that there is a list of Bunnings installers. Do you know where I can find this list please? Is it on the Bunnings website?

Minty

Dave-1

https://www.workshop.bunnings.com.au/discussion/comment/133602#Comment_133602

Afternoon @Minty

I dont think theBunnings installers list is published. I have come across them as I had heard about them and when my mum had her kitchen replaced she was given three peoples names. So not a direct recomendation but def something that was handy.

Id sugest the trades desk would be a good place to stop and have a chat to. Chats = information is the way I always think.

Finding someone to do the things the way you want it can be a pain. It is always a steep learning curve about differenat ways to do something. Has the installer other photos to show you of previous work they have done to put you more at ease? Maybe as a final suggestion, contact airtasker and ask what they could suggest? Surely they would have to have something in place to cover this type of deal?

Dave

MitchellMc

https://www.workshop.bunnings.com.au/discussion/comment/133602#Comment_133602

Hi @Minty

It's your shed, and it's up to you the way you'd like the base constructed.

We offer a shed assembly service, but it's for when you already have your base prepared and ready to go. They are unable to create a base and can only bolt the shed down to concrete or a timber frame.

Mitchell

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