Shed troubles

echidna

A few years ago, I built a large shed - The shed is constructed of steel uprights, timber rafters and 4" concrete blocks on a concrete base.
I made a decision that I would stone-face the building as otherwise it would look just like many of the agricultural sheds in the area. I did this myself and due to my inexperience and some rather bad advice at the time, it leaks like a sieve through the concrete blocks. (I used concrete blocks to create an arch effect over the windows and doorways, but this was a bad idea, as the water just soaks through!)
I have repointed the stonework, and had another bloke plaster over the rear wall of the building - with some success. Currently whenever there are gales and rain, I end up with puddles of water on the floor and very wet walls.
I did think about building an inner layer of 4" blocks and damp-proofing properly between the outer and inner layer and am still considering this, but wondered if anyone out there has any better (and cheaper) ideas. I also thought about plastering the inside of the shed in a "tank" effect but wondered whether this would cure the problem at all.
I have tried various paint-on water seals, but they are no good for concrete block walls.
Any helpful suggestions gratefully accepted.

gillad

there is nothing you can do to stop the dampness coming through the stone and blockwork but you can seal the inside with a "slurry"
http://www.safeguardeurope.com/products/vandex_super.php

http://www.dampstore.ie/index.php

echidna

Thanks Gillad - Sorry for delay in replying - have been away. Sounds like a slurry is a good option. Do you know if it can be applied to concrete blocks?
In all the articles I have read from your links (thanks for those) it is applied to a solid concrete wall, which I presume would be far less porous than concrete blocks.
Cheers

gillad

I don`t think it works as good on blockwork as it does on a plastered surface.The product i used was "aquastop tanking" which is on the dampstore link.Best advive is to get some and try it on a section of blockwork and if its not a good enough result,then plaster the walls and apply it.its a powder that is mixed with water and painted on ,It will take a few coats.
there is another product "brunopol iwp" on the same site that you can mix with the plaster .I`ve never used it but its worth checking out.

mickdw

Single leaf/solid blockwork is a disaster. Any sheds being built at houses that I have any input into are built with cavity wall. Step in raft also critical. You sometimes see people putting in a perfect house raft and then just a flat surface to build the shed on. Water will cross if no step provided.

gman2k

Just have to start planning a shed at he rear of my house soon. (shed detached from house)
I'm going to be putting the oil tank and water pump into it, and I reckon there's going to be more details involved than what went into the house!

gillad

it is very important that the floor level in the shed is higher than outside (as mickdw pointed out)other wise you will never solve this problem.

echidna

gillad wrote: »

it is very important that the floor level in the shed is higher than outside (as mickdw pointed out)other wise you will never solve this problem.

I agree Gillad - I have found out all of this after the fact unfortunately. Anyhow, as part of the shed refurbishment I am re-concreting the floor inside so it will be higher than the outside. Although the floor itself does not get affected by damp, because of the leaking wall problem, I tend to end up with puddles in the mddle of the floor. The floor was initially laid to provide a slope down to a central drainage channel, but as the purpose of the shed has changed, I decided to relay the floor so that this slope is taken out. They also laid an apron of concrete outside the shed entrance but even though there is a slight slope away, when the wind drives the rain, this is not adequate and the rain comes in under the shed doors.

Joey the lips

Hi Folks,Just a little bit of advice on the slurry and hope it helps. I woked for a company that use to supply it.

Its best applied to the outside of a wall. As the brick remains damp if you dont.

Its best applied to a plastered surface of sorts as gaps will allow water to penatrate past it.

Its best applied with a brush

lastly if you want you can paint or render over it..

echidna

Thanks Joey,
Applying it to the outside of the shed wall in my case is not an option, as I have stonework on the outside and I would not like to ruin it's appearance. Do you advise rendering the inside(over the concrete blocks), then applying the slurry and then rendering again over the top?

Joey the lips

No it cannot be applied inside because applying to the inside will actually cause the brick to hold water. So this will effect the outside in the long term

I cannot remember the science but essentially water flows from a low pressure to a high pressure or some sh1t like that. Essentially the outside of the shed is one pressure zone and the inside another. The water will do its dam best to get into that shed. When it hits the seal in the wall it will stop and mildew will grow. This is why it needs to be outside.

The only exception to this rule is cellers. These are sealed by a combination of injecting the brick and painting the wall. A very very expensive process for your shed.

echidna

Yeah, I don't want to go down that road. I realise the barrier on the inside might be a problem, but thought that if the floor of the shed was higher and the inner part of the walls were impermeable, then the water would have no choice but to drain out again, (currently it is draining into the shed) and although the outer part of the wall may be damp, it may be no wetter than what it is at present.

Joey the lips

echidna wrote: »

Yeah, I don't want to go down that road. I realise the barrier on the inside might be a problem, but thought that if the floor of the shed was higher and the inner part of the walls were impermeable, then the water would have no choice but to drain out again, (currently it is draining into the shed) and although the outer part of the wall may be damp, it may be no wetter than what it is at present.

You can phone the co;s listed above and ask them for rec's I am away from the company I was with 8 years now but the technology has not changed.

I also figure that your shed is unusable now so doing it on the inside might make it last 10 years useable,. The choice is your really but for my money I would apply it outside. You know its clear paste...

echidna

Oh really - it's a clear paste? That definitely "sheds" new light on the subject. (forgive the pun!) Thanks for your help, I will certainly look into it!:cool: