Another damp WS thread

[Squarethumbs]

Hi Guys

Nice forum!

We moved into our new house in August and realised my dream of having my own decent sized workshop I was over the moon. Being from a long line of carpenters (not one myself I hasten to add) and a Radio Controlled Plane enthusuast the existing 20ft x 11 ft workshop looked just the ticket.

All was well until Autumn set in. The corrigated steel roof sweat so bad all my tools, equipment and models may aswell have been sat outside so I proceeded in replacing it with external ply and felt. Ideally I want to build an apex roof with insulation for extra storage etc but that will have to wait for now.

Over the last couple of months the ply has got quite damp and started to mould badly. Ive bought a can of decking treatment for preventing mould and then plan to paint it matt white. Is there anything else I can do? At the moment I have one of the double glazed windows slightly open for electric to my temporary Koi pond outside. Is this my main problem?

Workshop is block built on concrete base. I need to get this WS organised ready for the renovation of our three bedrooms before a new arrival end of March but dont have a large cash flow at the minute to get it exactly how I want it.

Any suggestions are very welcome.

Thanks

Guy

 

[newt]

Welcome to the forum, the spam trap has been enabled with your message this will stop after a few posts. I am sure someone will be along soon to help with your problem.

 

[OLD]

My suggestion is to have the under side of the steel spray foamed say £280 any other methods would require removal of the sheets i can come up with a method (labour intensive) if you were ok to do this.

 

[Squarethumbs]

Hi

Thanks for the welcome. Maybe if I post a bit more my pics will be shown :lol:

OLD - Im not sure if you realised I replaced the corrigated steel with ply?
My problems not condensation anymore, its a damp ply roof.

I would try a dehumidifier but its a waste of time at the moment with the cable coming out of the window for my pond. I like the idea of having low watt energy saving bulbs in cupboards for tools but until I get a 'proper' leccy supply out there thats not an option.

 

[PowerTool]

Hello and welcome

Maybe if I post a bit more my pics will be shown :lol:

Yes - think you only need to make three posts for pictures to appear.

Andrew

 

[Chris Knight]

Hi Guy and welcome!

Here are your pics.

 

[Squarethumbs]

Thanks Andrew

Post no3

 

[Squarethumbs]

Thanks for the kind welcome also Chris, pics have come up now. A good idea to have spam protection like this, have seen too many forums ruined.

By the way the treatment I bought for the ply is Wickes Decking and Garden furniture wood preserver which I intend to let settle in before I paint it white to give better light reflection for working. Sound reasonable?

What I dont get is my garage also has a ply roof and god knows how old that is, probably just as draughty and lets water in through the garage door. Not a sign of mould anywhere.

heres the WS before I replaced the roof

 

[OLD]

The short term answer is to drill a hole and reroute the cable, stop any other drafts then get some heat in there dry out the roof sheets which i assume have sound felt over. Then paint the roof sheets to stop further absorption the long term answer is spray foam as sheet insulation under will always have gaps to the sheets where more condensation can form but to save expense you could use 50mm polystyrene best foil covered held tight to sheets but the ply will not last for ever.

 

[Squarethumbs]

Thanks for your advice.

I started drying out the ply last night. heater will go on as soon as I get home. I did think about drilling a whole for the cable. If it doesnt squeeze under the door I'll deffo do this.

I realise the ply isnt the best option for the WS. Its a short term solution until I can get around to contructing an apex with roof tiles. I may even consider rebuilding the lot to be honest and extending without her noticing.

Got to move that metal cabinet so I can get to the roof there and build another bench for building aeroplanes plus the kitchen cupboards are for storage.

I keep telling HID I must do this all first before starting on the house as an organised workshop is all important :lol:

 

[Digit]

That amount of dampness makes me ask if your felt covering is leaking.
My workshop roof went on in early October and is made from OSB with good quality felt on top.
I live near the coast and today it has been raining hard enough to defeat the wipers on my car, but no damp.
Unless the building was designed for use as a workshop a lot of the moisture is probably through the concrete, and waterproofing that may be desirable, as any heating will only make the dampness worse as the moisture is drawn up through the concrete by capillary action.

Roy.

 

[dickm]

Pretty sure that is condensation, not a leak, which usually shows up as a more defined patch, with a clear edge and dry outside the patch. (been there, done that)
Unfortunately, heating the air in the shop may also make the problem worse if it's cold outside. The waterholding capacity of the air will increase with temperature, but the roof sheet will still be cold, and you may get even more condensation on the underside.
I got a graphic illustration of this in an old garden shed, where the side that did not get the sun regularly had condensation on its underside in winter, while the sunny south side stayed nice and dry.
I'd go for insulation with a damp proof membrane on the underside, as soon as you can.

 

[Digit]

Yep. It's a whole body job I reckon Dick.

Roy.

 

[Squarethumbs]

First of all thanks again guys for helping out here.

Nope, definitely not leaking. We've had downpours here over the last few weeks and its been dry as a bone (well apart from a bit damp). The mould appeared when I stopped using the workshop leading up to and over Xmas.

When I got home today I noticed that the far wall where the window is in the picture is almost wet up to about 4-5 bricks up.

I agree with you. It needs insulating once Ive treated it. Can I paint the walls with synthaprufe whilst it is still damp/wet?

 

[Digit]

It can be applied on a 'damp' substrate. If the water is from above, eg, no gutters then okay, but if its rising from ground water an injected silicon damp proof course might be a better option.
Rising damp can often be differentiated from penetrating damp by a line of salts on the brickwork at the upper limit of the damp line.
The drier you make the inside the worse rising damp can become, if it is rising damp then the floor will definitely need proofing.

Roy.

 

[Squarethumbs]

Ahhhhhhh Roy you are a legend.

The pennys just dropped :roll:

Ive not got round to putting the guttering on yet, just not had time. the wall in question is at the far end, roof is sloping towards it so all the rain water just drips off the end.

Thats where the damp/water is coming from that end Im sure of it. All I need now is 5 water butts to catch all this blimin rain we're having :lol:

Thanks!

 

[Digit]

Oh goody! After me, Roy is a genius'. :lol: :lol: :lol:

Roy.

 

[Squarethumbs]

Hi

Gave the roof the once over this evening with treatment. Soaks in real nice, looks better already. I did leave my heater on and it seemed pretty dry so I went ahead. Better get it treated sooner rather than later. Second coat will go on tmw evening

Also found the long wall facing the lawn is very damp too. Theres a gravel path all the way round the workshop and on really wet days, I mean cats and dogs all day that path has been about 1" under water. Probably seen that happen only twice tho since we have been here and it receeds quite quickly. The path is old and the gravel is stuck together with mud. This is higher than the concrete base in some areas.

Seems to me this is penetrating damp? No marks on walls. Floor is dry. What I'm thinking of doing is digging the mud and gravel up and digging down a bit further say a foot and replacing with flint. Should act as a bit of a soak away?

 

[Digit]

Should act as a bit of a soak away?

Nope! It will act as a resovoire unless you ensure that it can run off somewhere. Building Regs recommend that ground around a building should be 150mm below DPM's etc to prevent splashing up onto the walls.

Roy.

 

[Squarethumbs]

Thanks again Roy

I know, the bloke who built it didnt do enough research. The concrete base is far too low.