Garage Workshop build - advice needed please

[Goesbysteve]

If the inside is dry I'd think you can put closed cell foam against the brickwork and it will remain dry?

It's a garage after all.

My understanding is the wall inside will be cold in winter at least and therefore any moisture going through to it would condense. Thst said if installed right PIR with a foil layer is a decent vapour barrier so little should get there however it’s not a perfect barrier and I’m not a perfect installer either!

 

[IBmatty]

As described it’s sounds not that different to one of the ”dependences” that came with my house here in France, although your roof timbers are in a considerably better condition that the ones I had to rip out. It’s on a slope and on one side there is a water risk down to a “déviateur d'inondation”. The local town hall paid for the wall (15mm block) facing that to be protected with an external cladding of 75mm insulation (kingspan/celotex type), glass mesh and finish render. I watched and learned and copied for the rest of the building and DIY’d it. Cost for my bit worked out about 18-20euro per m2 all in, this was 7-8 yrs back. The part of the insulation board underground was lined with a dimpled semi-rigid plastic that is bought in rolls here, not fixed, just held in place by the backfilling. I simply painted the inside walls with an exterior grade masonry paint. Use it for metal workshop and metal storage now, warm and cosy, dry as a bone all with no loss of space inside.

 

[Goesbysteve]

As described it’s sounds not that different to one of the ”dependences” that came with my house here in France, although your roof timbers are in a considerably better condition that the ones I had to rip out. It’s on a slope and on one side there is a water risk down to a “déviateur d'inondation”. The local town hall paid for the wall (15mm block) facing that to be protected with an external cladding of 75mm insulation (kingspan/celotex type), glass mesh and finish render. I watched and learned and copied for the rest of the building and DIY’d it. Cost for my bit worked out about 18-20euro per m2 all in, this was 7-8 yrs back. The part of the insulation board underground was lined with a dimpled semi-rigid plastic that is bought in rolls here, not fixed, just held in place by the backfilling. I simply painted the inside walls with an exterior grade masonry paint. Use it for metal workshop and metal storage now, warm and cosy, dry as a bone all with no loss of space inside.

Thanks, very interesting. The glass mesh, is that fibreglass mesh? Was that to provide structural rigidity? I think I may be just too damn close to the secondary tributary on one side to do anything there. I’ll need to show photos of that as it won’t be obvious from the photos I’ve posted so far.

 

[david.tamlaght]

Have you thought of harnessing the power of that river to produce electricity?

Deep pockets and a very tick skin required in dealing with this issue.
Planners ,rights of access unless you own the stream,water agencies etc,cost of connection to the grid unless you intend to store power for your own use only which is also costly .A small wind turbine on your own patch and some solar panels would be a more realistic option
I ve been involved in this side of things and the figures are eye watering to say the least .Not for the faint hearted to install a water turbine and you can't just lower it into the stream .major engineering job

 

[johna.clements]

I was thinking the same but living in a conservation area may cause issues even when it’s unseen by anyone and the garage is hardly in keeping.

There is a fairly decent stone bridge 50m away downstream. It’s field upstream and not woodland though it only takes one tree. I think the flood defences on the door plus suitable waterproofing on outside of walls would be the best I can do. Is Black Jack high up the wall enough for that?

I would have thought that a row of blocks (to match the garage) or paving slabs (to match local stone) to retain the 300mm of soil next to the garage would be considered gardening. I am no expert in planning law. When the garage was built it is unlikely that the soil was supposed to be piled up against the wall so the plans that the council has will reflect this. You will be just doing some gardening to return it to the design condition.

The plans may be available on the councils website if the garage was built in the last few years. If not do not ask,you do not want them to investigate.

If the road over the bridge is lower than your garage then any flash flood should drain quickly. If a tree in the bridge would cause water to back up to the garage I would make sure I have the flood authorities number to hand and make friends with the local farmers who own JCB type machines.

I assume that the garage is the dark building behind the for sale sign. I also assume that the dark line between the garage and the building with the for sale sign is a small stream. The two culverts that flow under the road are likely to get overwhelmed in a flash flood, I would assume that the water flows across the road once or twice a year. They would be very dangerous to try to unblock from inside the stream.

I would put two coats of black jack plus your door defenses. You already have your electric coming down rather than up so I assume that some thought has gone into flood resilience to the garage.

 

[Goesbysteve]

I would have thought that a row of blocks (to match the garage) or paving slabs (to match local stone) to retain the 300mm of soil next to the garage would be considered gardening. I am no expert in planning law. When the garage was built it is unlikely that the soil was supposed to be piled up against the wall so the plans that the council has will reflect this. You will be just doing some gardening to return it to the design condition.

The plans may be available on the councils website if the garage was built in the last few years. If not do not ask,you do not want them to investigate.

If the road over the bridge is lower than your garage then any flash flood should drain quickly. If a tree in the bridge would cause water to back up to the garage I would make sure I have the flood authorities number to hand and make friends with the local farmers who own JCB type machines.

I assume that the garage is the dark building behind the for sale sign. I also assume that the dark line between the garage and the building with the for sale sign is a small stream. The two culverts that flow under the road are likely to get overwhelmed in a flash flood, I would assume that the water flows across the road once or twice a year. They would be very dangerous to try to unblock from inside the stream.

I would put two coats of black jack plus your door defenses. You already have your electric coming down rather than up so I assume that some thought has gone into flood resilience to the garage.

Thanks thats very useful. I’m certainly not the only resident liable to flooding here and the farmers use the bridge to get between fields. I think that should be dealt with fairly quickly.

I’m going to check my records passed to us on purchase and a light investigation with council, as you I don’t want to trigger an investigation.

I’ll take some more photos when the rain stops over the weekend to show things better.

l’ve started to research flood defences. Designs seem to be very similar between manufacturers for entranceway boarding. The two external doors on the house will be the priority though. I may invest in a flood “snake” that automatically expands when in contact with enough water. That might afford some small flood mitigation. The workshop build inside will not start for a while now. Maybe spring.

I really appreciate your thoughts and advice.

 

[johna.clements]

Thanks thats very useful. I’m certainly not the only resident liable to flooding here and the farmers use the bridge to get between fields. I think that should be dealt with fairly quickly.

I’m going to check my records passed to us on purchase and a light investigation with council, as you I don’t want to trigger an investigation.

I’ll take some more photos when the rain stops over the weekend to show things better.

l’ve started to research flood defences. Designs seem to be very similar between manufacturers for entranceway boarding. The two external doors on the house will be the priority though. I may invest in a flood “snake” that automatically expands when in contact with enough water. That might afford some small flood mitigation. The workshop build inside will not start for a while now. Maybe spring.

I really appreciate your thoughts and advice.

I have had little involvement in building but I think that you should take into account the wall thickness is only 100mm on your chosen flood defence. obviously a thinner wall will not be able to take as great a depth of water as a thicker wall.

I assume that the the building (old mill?) at the bend of the river is most at risk.

 

[Goesbysteve]

I have had little involvement in building but I think that you should take into account the wall thickness is only 100mm on your chosen flood defence. obviously a thinner wall will not be able to take as great a depth of water as a thicker wall.

im not sure I follow.the metal or plastic barriers are specially made for doorways and garage door ways.

I assume that the the building (old mill?) at the bend of the river is most at risk.

He says the same but has an 450mm wall built against river at the edge of his patio. However riverside ground lowers towards the front of our property to the stream at our side. So technically we are lower than the mill.

 

[clogs]

just to add, this stuff works very well for underground wall protection.....along with suitable drainage....

Thats a stunning part of the world.....

 

[Goesbysteve]

Flood warning in place here. Interesting timing.

I took some more photos and made a closer inspection rather than relying on my memory. The rear quarter of the garage is probably under more like 500mm. It was starting to hammer down with rain again so I haven’t measured i just looked along the wall and counted courses.

it may not be clear from photos just how close the left hand side is to the smaller stream both in lateral and level.

Also how close the rear of the garage is to the heating oil tank. If built now it wouldn’t be to refs due to proximity. It certainly makes any construction very difficult as I can’t risk subsidence under the tank’s slab. I think that’s beyond diy skill, certainly mine. I think that includes to paint the wall down below the current ground level.

The silver lining is I have confirmed there is a DPM sheet on the garage slab although it is also well underground toward the back.

There appears to be a drain from the underground wall of the rear into the stream but that would t help if the level of that water rose above it. I will do an explorative dig to see if there is evidence of gravel against the wall. I’m also going to try to find details of who built the garage. that might get me more details but I estimate a decade has passed.

I am yet to test the paint used to see if it is bitumen but it looks very matte and thin in depth to me.

Talking further to neighbours water has not come to more than lapping at the gravel access road that immediately boarders our driveway. Maybe 15m from the from of our garage. I will try to estimate/measure the rise from there.

 

[Goesbysteve]

just to add, this stuff works very well for underground wall protection.....along with suitable drainage....View attachment 145008

Thats a stunning part of the world.....

Is that to be stuck to the wall? Do you have a link I can read more about it?

it is indeed stunning, both this part of Wales and this particular village. It’s in a conservation area though outside the National Park. That may still mean I end up requiring permission in order to do any works on the outside, even the cladding I want to add. Has to improve the look over painted breeze blocks right?

 

[johna.clements]

im not sure I follow.the metal or plastic barriers are specially made for doorways and garage door ways.

I would say you want one for a garage door way rather than a house door way. (if they make them differently). The thicker the wall the more lateral load that it can take.

 

[Goesbysteve]

I would say you want one for a garage door way rather than a house door way. (if they make them differently). The thicker the wall the more lateral load that it can take.

well the ones I looked at were specially designed for double garage doorways and businesses. So I kind of hope they are. I’m not thinking of putting several house door way ones together lol

 

[johna.clements]

Flood warning in place here. Interesting timing.

I took some more photos and made a closer inspection rather than relying on my memory. The rear quarter of the garage is probably under more like 500mm. It was starting to hammer down with rain again so I haven’t measured i just looked along the wall and counted courses.

View attachment 145011

View attachment 145015

it may not be clear from photos just how close the left hand side is to the smaller stream both in lateral and level.

View attachment 145014

Also how close the rear of the garage is to the heating oil tank. If built now it wouldn’t be to refs due to proximity. It certainly makes any construction very difficult as I can’t risk subsidence under the tank’s slab. I think that’s beyond diy skill, certainly mine. I think that includes to paint the wall down below the current ground level.

View attachment 145010

The silver lining is I have confirmed there is a DPM sheet on the garage slab although it is also well underground toward the back.

View attachment 145013

There appears to be a drain from the underground wall of the rear into the stream but that would t help if the level of that water rose above it. I will do an explorative dig to see if there is evidence of gravel against the wall. I’m also going to try to find details of who built the garage. that might get me more details but I estimate a decade has passed.

View attachment 145009

I am yet to test the paint used to see if it is bitumen but it looks very matte and thin in depth to me.

Talking further to neighbours water has not come to more than lapping at the gravel access road that immediately boarders our driveway. Maybe 15m from the from of our garage. I will try to estimate/measure the rise from there.

The blocks including joints are 225 high by 450 long. So there is about 675 depth of soil above the garage floor at the down pipe.

In the last photo there is the pipe which looks like the end of the down pipe and a lower corrugated pipe. I would guess that the corrugated pipe is a land drain running around the back of the garage. I would leave everything as it is and not do any digging. The corrugated pipe may have stone or coarse sand around it with a textile membrane to stop contamination by the soil. If the stone / sand gets contaminated it will not work as well.

Also you have the gas line from your propane tank. A bit of a pain if you have to get that fixed.

I do not think that there is anything you can do at the rear of the garage that would be easy.

 

[Jameshow]

well the ones I looked at were specially designed for double garage doorways and businesses. So I kind of hope they are. I’m not thinking of putting several house door way ones together lol

How much are they?

Surely you could make them out of 18mm buffalo board?

 

[Goesbysteve]

The blocks including joints are 225 high by 450 long. So there is about 675 depth of soil above the garage floor at the down pipe.

In the last photo there is the pipe which looks like the end of the down pipe and a lower corrugated pipe. I would guess that the corrugated pipe is a land drain running around the back of the garage. I would leave everything as it is and not do any digging. The corrugated pipe may have stone or coarse sand around it with a textile membrane to stop contamination by the soil. If the stone / sand gets contaminated it will not work as well.

Also you have the gas line from your propane tank. A bit of a pain if you have to get that fixed.

I do not think that there is anything you can do at the rear of the garage that would be easy.

No that was my assessment too. whilst getting dinner out of the overflow freezer in there I checked around for any sign of water or damp. We have had a lot of rain last few days. No visual sign of damp. Only thing I found was some concrete/cement mortar break up along the inside rear between the wall foot and the interior floor. Only a localised area affected maybe a few 5-10cm patches over a length of a metre. It’s part of the cement that runs all the way round so I assume the bonding between wall and floor. I’m no builder as you can tell. No sign of similar damage anywhere else I could get access to easily. The floor and wall look in excellent condition. No cracks on the floor.

This is turning out to be the project that keeps giving!

Tomorrow I’m going to give it a poke to see if it’s just the surface And try my moisture meter in it. Is patching this a good idea? I may wait for a drier week though there is no moisture in there or around it I can see or feel.

 

[Goesbysteve]

It’s just some surface crumbling. Had a friend in the trade coming look. His view was also leave well alone, it’s a well build garage and dry as a bone inside. He discovered there is a thick plastic barrier all the way round the wall at ground level, rising up the wall as the ground rises. There is also a second French drain on the long side where the ground rises to the rear.

super news!

 

[Goesbysteve]

Having been distracted by the flood issue for a bit, and being under the weather, I’m now back at worrying about putting 7 x 12.5mm 29kg each plasterboards up on my bottom roof truss. If I sistered the rest of my 2x3s with c24 would that actually make a difference or just add weight on the existing truss structure with no benefit to weight bearing? How would I get 3m lengths up there anyway, I’ve seen folk put them up in two lengths with a bolted metal plate through new and existing. Do they need to go the complete length of existing truss bad onto wall plate? I think there are metal “hangers” that the existing wood fits in, what are my options for ensuing the new sistered wood is flush against the existing?

Is that just a naive view of structural design? Actually I think I know the answer to that latter question!

On my walls I still plan fixing PIR to battens abs taping then boarding over with 12mm MDF. I want to put shelves up using 2x3 or 2x4 near free standing structure screwed into wall. Worried about the screws piercing the foil on the PIR. Do I need to be? is there a fixing method I can use that won’t risk that?

Sorry if this appears to be going over ground ore previously answered. It’s just my reading of other similar plans and replies alternating between “don’t they weren’t designed for it“ and “oh plenty do it just throw some chipboard up there and store a car engine.”

Thanks in advance.

 

[Colin the helper]

I

 

[d3m0n]

Following, I have a similar predicament in terms of the roof; also having moved recently into a fairly new build (2007-ish) with a separate garage that i would like to "workshop". Our garage roof is almost identical structurally and would also like to board out for storage and then plasterboard. I was also thinking of running extra material the width but didn't think i could without reinforcing the hangers, but the more I look into it common sense says don't bother and just board over it tie it all down and you will be ok, but then the flip side is can those hangers hold all the additional weight of the board, the plasterboard and whatever I end up putting up there (likely more wood + other household goods (Xmas stuff, my fishing gear, etc))