Condensation in Industrial Unit

Evening all,

I bought an industrial unit last year and moved my engineering workshop into it during the summer. we renovated the building completely which included putting a brand new suspended ceiling up in the area above the mezzanine floor. The total ground floor space of the unit is about 6000 sq ft. and about 9.5mtrs from floor to top of building.

The main factory area has no suspened ceiling.

The factory is full of CNC machinery which does run coolants which I guess can produce some moisture. The main culrits of this though are extracted with proper units. The machines generate some heat and keep the factory fairly warm too. We had no gas blower working last year (old one was unsafe), so although the harsh days in December were pretty cold in there, the place in the main part kept warmish. Ill be installing a new gas space blower this summer.

My problem is when the cold weather started (Oct onwards), we started getting what we believed were leaks from the ceiling. I had the roof checked and all was fine. It turns out it was condensation leaking from the top of the building. There are steel support running across the building supporting the roof and the condenstion only seems to come fromm areas running along these beams.

The new suspended ceiling has been wrecked too in the area above the mezzanine as the condensation has dripped onto the new tiles staining them.

I dont know how to stop this happening. Id like to get it fixed this summer so I can replace the stained tiles and know it wont happen next winter. Id also like to stop the moistiure dripping from the ceiling onto my sensitive CNC machines below.

Any help how I can stop this would be greatly appreciated. OR indeed if anyone knows of any experts I can get in to advise.

Many thanks.


Neil

You could line the underside of the roof sheets, or problem beams with insulation to remove the cold surface for air to condense on.

Alternatively, you could try and keep the air circulating at roof level so that it either does not condense or it evaporates quickly.

Have a look up next time you're in B&Q or Asda at the fans and air ducting

A building surveyor should be able to help, but it may be pot luck whether you find one suitably qualified or even willing to help on anything specialist like this.

The only other profession I can think of would be someone from M&E service industry - try www.cibse.org

The suspended ceiling caused the problem by stopping air circulation above it.

Just like a domestic loft with no ventilation.

Hi Neil,

There are companies which specialise in spraying polyurethane foam insulation onto the steels and roofs of industrial buildings to help with the problems you describe.

Using spray foam will remove cold spots for condensation to form on but wont help with the high moisture content in the air. If the budget can stretch a combination of sprayed insulation and a decent air extraction system would be best.

Neither are particularly cheap and spayed insulation can make replacing the roof more time consuming if you ever need to.

I would look at ventilation first. This will probably be the cheapest option and you might not need anything more. Be aware also that the new gas blower will increase temperature but will also increase water vapour so might even make things worse. Remember condensation is more a factor of temperature difference between air and surface rather than just temperature on its own.

Hi

Your first step should be to insulate the roof from the outside, minimum 100mm PIR or Polystyrene Insulation known as a warm roof construction. In theory this keeps the condensation zone outside of the building. For more information do a web search on 'warm roof insulation' it will also tell you of the benefits over a cold roof design.

Second step if needs be insulate the internal face of the external facing walls again ideally 100mm but you could go down to a thickness of 75mm.

Possibly not quite as simple as I am making it sound, but it will give you a step in the right direction.
Don't just jump in, do some research and more importantly plan what you intend to do, maybe you will need to prioritise in which case the roof insulation should come first! Then the walls and monitor conditions before you go jumping to the next step of introducing heating as you could find the demand for heating dropping significantly with the added insulatio

Next important point - do not go for 'gas blow heaters' what you need are gas fired high bay infra-red heaters - and the fumes will be ducted out of the building. Also infra-red is not affected by convection currents which is what blow heater rely upon to distribute the warm/hot air and the convection currents (heat always rises) can soon take the heat away from the place where you want it most.

Ventilation is important, but you should leave this item until you have tested the above improvements.

Regards

Thanks all for your answers, I have a company coming in tomorrow to offer some advice, and I will write back on here when I have there recomendations and what I decide to do.

Neil

PS: for info the building already has 75mm insulated sheets on the ceilings and walls.

Hi

Insulation thickness sounds a bit dated, you should be looking at a minimum of 150/175mm thickness. Rather than remove the existing it may be possible to add a further 100mm thickness to the existing, although you would then need to re-apply a finishing membrane to avoid degradation of the insulation material.

75mm probably met the standards at that time, which would have been significantly better than no insulation. Condensation is likely to be down to the fact that the roofing material is impervious and not letting moist/saturated air escape and condensation is then forming on the underside of the roof structure. Water being water, it will seek the path of least resistance which is downwards onto your machinery.

As before this situation will not be helped by the gas blow heaters, and if you are going to introduce ventilation, don't forget to add heat recovery units to the ventilation system you install otherwise all that lovely energy will be wasted. What you could consider are some high bay circulatory fans which simply push the air about the building rather than allowing the hot air to rise.

Maybe not as full or as simple as I am making it sound, but I would be interested to hear about the recommendations that are made before you go jumping in with both feet!

Regards

The condensation is occuring due to the fact that you have enclosed the roof space with the suspended ceiling thereby cutting off any ventilation. The moist air in the void cools (particularly on the cold steel surfaces) and condenses.

Just to clarify my previous post, your first option should be to ventilate the void. A couple of ventilation fans positioned to move air between the void and the heated space below might well be all you need. No heat will be lost as you are simply moving air around within the building. This will be very inexpensive and might well be all you need to do.