Severe wet rot problem on older 5x3 single garage. Is this salvageable?

[BareBear]

Hi folks,

I have an old 5x3 single garage that I want to convert to a workshop. I intend to have another shed in the other part of the garden for bikes, sledges, lawnmower, garden tools, etc.

The problem is, the garage is sat on a concrete base set in a small cut out coming down a reasonably gentle slope from the back of our garden, and the problematic side/corner sits along the perimeter line of our property bordering with the neighbour.

Because of this, little to no maintenance seems to have been done to protect the lower frame of the garage and it has rotted away. I’ve managed to get a couple of videos and a lot of pictures of the issue with the help of my son and would love to hear the thoughts of the community as to whether or not it is possible, or even worth it to repair before doing the workshop conversion.

I want to cover the insulated walls with OSB, and set up benches and areas for wood working machines. It would need to eventually be water tight.

The rest of the shed frame is sound, but the cladding is warped and almost see through in places, so there would need to be some work on the cladding too. Having said all that, the whole thing is solid. The framework is made of very well treated timbers and I think if it had been maintained at all, the rot would not have happened. So there may be some life left in the old dog yet.

What do you think? Should I repair or remove and replace?





Flickr photo album - Garage Rotted Timbers

 

[John Brown]

Hi folks,

I have an old 5x3 single garage that I want to convert to a workshop. I intend to have another shed in the other part of the garden for bikes, sledges, lawnmower, garden tools, etc.

The problem is, the garage is sat on a concrete base set in a small cut out coming down a reasonably gentle slope from the back of our garden, and the problematic side/corner sits along the perimeter line of our property bordering with the neighbour.

Because of this, little to no maintenance seems to have been done to protect the lower frame of the garage and it has rotted away. I’ve managed to get a couple of videos and a lot of pictures of the issue with the help of my son and would love to hear the thoughts of the community as to whether or not it is possible, or even worth it to repair before doing the workshop conversion.

I want to cover the insulated walls with OSB, and set up benches and areas for wood working machines. It would need to eventually be water tight.

The rest of the shed frame is sound, but the cladding is warped and almost see through in places, so there would need to be some work on the cladding too. Having said all that, the whole thing is solid. The framework is made of very well treated timbers and I think if it had been maintained at all, the rot would not have happened. So there may be some life left in the old dog yet.

What do you think? Should I repair or remove and replace?





Flickr photo album - Garage Rotted Timbers

I'm no expert, but you really need to get the timber away from the concrete base, or it will continue to rot. Is there anyway you could jack it up and lay 2 or 3 courses of bricks?

 

[TheUnicorn]

from what I've understood from your description the problems are moisture being caused / held by the ground level and airflow on the outside, unless you are able to address that you can expect the same issues again in a couple of years time.

 

[Sachakins]

Looks nasty. Giving what you need to do to salvage it, maybe a better option is to dismantle it, salvage the good timbers and burn the rest.

You could then address the issue of the damp corner ground. Is it possible to rebuild slightly further in from the boundry using new and reclaimed timbers.

You could add a brick riser support to lift it up and away from the source of the wet rot.

I think renew/rebuild would be my preferred route, having already had a shed with similar corner issues I chose the tear down and rebuild option, adding a course of brick to raise the floor. Not had any issue with that corner since, done about 4-5 years ago.

 

[joncooper27]

Looking at the pictures there is no membrane to stop moisture rising, no guttering so the water will just run down the front of the shed poor air circulation.
To me the choice is either rebuild the lower section with moisture damage and put a damp membrane in and lower the ground level and fit guttering. Then a good timber treatment.
Or rebuild the whole shed with membrane air circulation and gutters.

 

[Dabop]

Not quite as bad as my mums old garage- it had about 8ft literally 'hanging in the air' like that- it was actually quite easy to fix (even for a then 13 year old like me) although probably not quite 'up to standards' these days, it is still standing lol

Just used a treated timber replacement for the floor beam (heavily coated with tar thanks to the neighbour who worked on the council road repair team lol- he took it into work and literally 'hot dipped' it in one of their trucks tar hoppers) then cut off the lower ends of the uprights that were rotted, put 'concreters plastic' down as a barrier and put the new beam down along the floor, then using the jack out of mums car and some clamps and scraps of timber as braces, jacked up each vertical and put in a new 'cut to length bit' in (that way the side door opened again, the whole section of wall that had rotted had the small door in it and had settled down until the door was supporting the wall!!!) and then put a slightly longer bit along side and screwed it all together before letting the jack back down again... now you could open the door even!!!

Pleased as chuff I was at the time about my fix LOL (and I know the people that now own the house after she sold it after several new owners, and its still like new) that was over 40 years ago and still standing!!!
(It didn't actually get bolted down until a couple of years later as we didn't have an electric drill for concrete at the time- all we had was a bit and brace lol)

That place always had drainage issues, as it was literally the lowest block in the street, and everyone elses yards drained into ours, so when it rained heavily, the entire back yard would be several inches deep in water- that was another one of my early 'projects'- 13 years old and digging a trench and putting in a new drain from the nearest one (in the driveway in front of the garage) back into the yard at the back of the shed to drain the water in the back yard away- it was about 3 inches lower than the drain in the driveway and would just sit there until it evaporated away... :-O

Mum would have had a fit if she had seen it in that state- we were dirt poor at the time, but she kept it tidy....

 

[clogs]

dadop....like ur style.....

house builders are same all over the world........
nobody cares at all....
My first *new* house had a water problems when it rained.....and it always rains in Manchester....
every house since has been on a hill just for that reason.....

 

[Jameshow]

I'm no expert, but you really need to get the timber away from the concrete base, or it will continue to rot. Is there anyway you could jack it up and lay 2 or 3 courses of bricks?

That's a good idea cut round in sections say 4' at a time, 3 courses of bricks preferable engineering brick lay the staggered as you would a wall, DPM on top and a new base plate on top of that..

 

[Jacob]

I'm no expert, but you really need to get the timber away from the concrete base, or it will continue to rot. Is there anyway you could jack it up and lay 2 or 3 courses of bricks?

My thought too. What about bolting on a 2x4" all the way round at say 2ft above GL and then jacking/levering the whole caboodle off the ground and putting in some blocks and damp proofing? Drop it back and then repair in situ?

 

[Dabop]

dadop....like ur style.....

house builders are same all over the world........
nobody cares at all....
My first *new* house had a water problems when it rained.....and it always rains in Manchester....
every house since has been on a hill just for that reason.....

That entire town has always had drainage issues, and its getting worse- it is an island, made of sand, and the highest point is only about 1m above sea level- we used to get the street drains backwashing on king tides as the sea was higher than the drains (they had cast iron 'flappers' that were supposed to stop that happening, but they were often rusted in place)
It is now a regular occurrence there now, happening more and more often
:-(
(Friend of mines mother had a 'fish and chippies' just around the corner from that picture, and every king tide, the water was up over the footpath up to the front step of the shop...)

King tides flood town's streets newspaper article

 

[BareBear]

Thanks everyone. I’m generally feeling that I should go ahead with a repair and having looked at a few shed jack up videos on YouTube, it’s definitely something I could do.

I could possibly do the brickwork myself if it’s possible to make it one course of concrete block at 215mm high.

I like the idea of laying in some galvanised banding between the existing concrete base and the new concrete block, anchoring the band to the base, then putting the mortar over it, then attaching them to the timber frame. That would let me get the DPM along the top of the new concrete block without bursting through it with fixings.

 

[PDW125]

I could possibly do the brickwork myself if it’s possible to make it one course of concrete block at 215mm high.

Blocks tend to be quite porous - I would go a couple of courses of engineering bricks with a DPC on the top and then it’s belt and braces. Use 100/600mm roof straps to hold the lot down - angled ones Tapcon screwed into the concrete floor and then screwed to every other upright.

 

[BareBear]

After a lot of thinking, we have decided to buy a new shed and put it on the existing concrete base. I won’t sit it on a layer of brick though. Instead I’m going to sort the drainage around the shed so that the water runs off, and add gutters and a sealed “weather bar” type overhang so that no water runs under the frame from the outer cladding.

I’m laying a DPC underneath the frame and adding a breather membrane, insulation and OSB sheets to create a cosy space. There will be vents at both ends of the workshop.

I’m keen on sealing the base of the frame but unsure what part to seal, the outside of the frame, the inside of the frame between the frame timber and OSB, or inside the OSB. Any advice on this would be greatly appreciated.

I’m interested in putting down a matting on the concrete base when it’s finished. Any suggestions?

 

[Max Power]

My thought too. What about bolting on a 2x4" all the way round at say 2ft above GL and then jacking/levering the whole caboodle off the ground and putting in some blocks and damp proofing? Drop it back and then repair in situ?


I did exactly that with an 8m x 5m wooden building, raised it and put three courses of concrete blocks under. It will outlast me and probably another generation now.

 

[budgie98]

I think that, before I did any building, I'd wash the concrete base with strong bleach in an attempt to remove any mould spores.

 

[BareBear]

It’s been a few months since the new shed went in and I am very happy with the space. However I probably need to do a bit of tweaking to make sure it lasts and doesn’t rot around the base. Here are some pictures. I laid slabs with a run off. The bottom of the cladding comes down the side of the concrete slab where the frame sits flush with the outer edge. There is a 20mm gap between the bottom of the cladding and the slabs.

Any advice on the back where it’s pooling would be appreciated thanks.

I’ll add some pictures of the build soon.

 

[Sachakins]

Hi, the cladding seems very close to the flags, any dirt or debris or over winter freezing likely to breach the gap and cause early deterioration of tour cladding.

Are the flags at side sat on the same level as the base foundations?

Personally I would remove them to take away the risk of bridging to your cladding.

Hope you're enjoying the new space.

 

[toolsntat]

I think I'd loose the slabs and get it gravelled for starters.
Cheers, Andy