24 replies to this topic

[s2ulk]

Hi all, I recently acquired a 1999 Cooper which has led a fairly comfortable life spending the last twenty years living at the back of a mechanic’s large garage. I don’t have a garage attached to my house and so have rented one from the council. It’s basic but seemed ok - brick wall construction and concrete floor with a corrugated roof on wooden rafters.

I put a humidity monitor in there a couple days ago and parked the car on a rolled out section of carpet. I went to check on the car this evening to find that it is basically stood over a puddle of water (carpet underneath completely soaked) but the water doesn’t appear to have come in under the garage door and the walls and roof are dry. The bodywork of the car itself was also dry. So the water seems to be coming up through the floor (or potentially at the level of the lowest course of bricks in one side of the garage). The humidity monitor is also showing an average of 97%.

So question in terms of rust prevention is: if I can’t get a ‘dry’ garage from the council, am I better off leaving the Mini in the current garage where it won’t come in direct contact with water but is sat in very damp conditions or am I better off keeping it on my drive under a winter cover? Dehumidifier/carcoon is not an option in the garage as it has no power.

Thanks in advance

[cooperd70]

If the garage is going to be damp then during very cold spells of weather you'll find surface rust on under bonnet ancillaries and anything aluminium (SU carb) will start to fur-up. If the garage is opened and air circulated then this will minimise the corrosion.

If you park the car up on your drive with a car cover you won't experience the above, but if you live somewhere that can get quite windy then you may find the car cover will start to rub the paintwork.

I've experienced both of the above situations.

The best solution would be to get a dry garage from the council....if they have one.

[absx2]

Living in the deep wet Cornwall where the humidity in the summer is in the 80`s I use a lot of spray oil 3 in 1 and  AC90 type stuff and spray it everywhere.

It soaks in everywhere and keeps moisture out. I even oily rag the paintwork and pump the tyres up to 55 psi if it`s not going to get used for a while.

I have an original paint 1990 Cooper that i`ve owned from 3 years old and it`s still looking mint, when the oil gets cleaned off that is 

[mab01uk]

Later Minis like the MPi rust far worse than earlier Minis but any Mini standing on wet ground with little air circulation will rust badly starting with the floor/sills area that sits just above the wet garage floor and will suffer condensation both internally and externally. The rest of the car will follow over time and the interior seats, etc will get mould growing on them in a short while.

Your Mini would be best in a dry garage with good ventilation and dry floor but even being outside where the wind will keep air circulating and dry the car off is better than a cold, damp garage. A good breathable car cover will protect the paintwork outside but as said windy weather can cause problems and many cheaper covers rapidly degrade in sun and rain so need regular replacement.

Edited by mab01uk, 23 October 2023 - 08:23 AM.

[roblightbody]

I have a similar problem.

My choices are :-

Outside under a quality cover

In a leaky but draughty garage inside a carcoon.

[DeadSquare]

Judging by the national news, the last few days have been rather wet, so it looks as though your humidity monitor may be working.

 

If the carpet is damp, bin it,

 

If the walls and roof of the garage are dry, there is no reason why the car shouldn't be in the same condition.

 

There may be occasions when the car is cold, but surrounded by warm damp air, which condenses on cold surfaces, either in a garage or under a canvas.

 

The biggest pro is that you can work on a car in a garage;  there is every incentive not to work on one under a canvas sheet.

[eric67]

I’d be inclined to stick with the council garage and cover the floor with a sheet of damp proof membrane. If you get a big enough sheet you’ll be able to run it up the walls and seal it with aluminium foil tape to keep the moisture out. I did this once and it worked well for a relatively small outlay. I also used strips of 12mm OSB/plywood to drive the car onto to avoid ripping up the membrane.

[MatthewsDad]

The damp is coming up through the floor as there isn't a damp proof membrane below the concrete. As above try to seal the floor with visqueen sheeting before parking your car on the visqueen. If there is no damp proof layer under the car in an unventilated garage you'll have problems. Try to insert air bricks or similar in the wall to get improved ventilation.

[Bobbins]

A friend stores his Caterham in a council garage and uses a Carcoon powered by a “leisure” battery. He has two batteries and swaps them over every couple of weeks, a leisure battery is fine for around two weeks with the current draw of the Carcoon fans.

[mab01uk]

If you do go for the council garage make sure the doors have some good security locks fitted (most standard garage doors are very easily opened) especially if situated in a remote place or area that can be accessed by the general public. Also ensure the car is not visible through any gaps or windows to potential passing thieves....

[s2ulk]

Thanks all for the very helpful input. The car cover fortunately arrived today (it’s an indoor/outdoor which I was going to put over the mini when in the garage). When I saw the state of the floor today (see photo) I thought it’s best to extract it from there for now and put it on my drive. The walls and roof of the garage are dry and there is a damp membrane between the first and second course of bricks but that means water can get in through that first course. So it’s either coming through the bricks or up through the floor itself. There is one air brick (size of two regular bricks) up high on the back wall. I will see if the council has a dry alternative failing which I like the idea of damp proofing it myself (may even screed over the membrane as have done that before at home) - the location of the garage is very good in a safe area with plenty of onlooking houses so I would prefer to keep it there if possible (and totally agree with the comment re working on the car in the garage which just won’t happen with it sat on my drive).

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[smurfomatic]

I had similar damp coming into my brick garden shed, which was (for some reason) built with a step down so the floor was below ground level. Painted the floor and first few bricks with bitumen paint, and not had any problems since.

[coopertaz]

keep car out of garage that damp at least on drive you have air flow around car just use a good outdoor storm grade cover and remove every couple of weeks even under these roof gets damp on it. as you say may well be comming in below damp course. my garage floor has no dpm and is dry but have air flow through roof void

[DeadSquare]

The water in that photo isn't damp. 

 

Check for blocked gutter / down-spout and anything at the back that might raise the outside water level.  Ask adjacent users about their floor.  Drill hole through floor at the deepest point. 

 

A slight slope on a screed would let the water drain, but you don't want any excess water in there.

 

That handy airbrick makes a "Superser" gas heater safe.

 

A caravan solar panel on the roof would keep the battery charged, and run and LED on dull days.

[ac427]

Could you go full on with a mastic gun to see the roof leak?