INSULATION, HEATING & DAMPNESS
I suppose it depends where you are from, how “hardy” you are, how much you want to “rough it” in life, and how desperate you are to save money; but I would definitely come down on the side of those who argue that you should insulate your home. Not only is it important for the environment, but it will save you money and make life more comfortable in the long run.
I couldn’t believe that the majority of Uruguayan homes (apartments and houses alike) don’t have any form of heating system or insulation! Some have open fires, some have stand alone gas heaters or plug in electrical heaters, and some have NOTHING! Air-conditioning I could live without (there tends to always be a good wind in Montevideo and along the coast, although if you plan to live in the interior you may want to at least install fans). However heating in my opinion is essential, and insulation even more so! Uruguay is a very damp country during winter. It may not reach freezing very often (if ever), but the mere lack of snow or frost does not make cold wet weather combined with a biting wind a comfortable climate!
In general, thermal insulation seems to be viewed with much disdain by most Uruguayan contractors. It is considered a pointless waste of time and money. I guess this ties in with a “Uruguayanism” that I mentioned earlier in that culturally they do not think about long-term savings, but how to save money right now by purchasing cheaper products or simply not purchasing anything. One expat I know even went to the effort of showing his contractor the logged difference in internal temperatures after installing the insulation he had fought so hard for, but his contractor was still not convinced of its worth. In Uruguay they believe that a layer of waterproof paint under the base of the walls is sufficient damp proofing! As such I have been in more than my fair share of apartments with obvious dampness seeping through the paint. Of course this isn’t helped by the general lack of double glazed properly sealed windows in a country bordering the Atlantic ocean, but thats another issue!
I have heard it argued that overly insulated buildings are actually at a disadvantage during summer unless there is sufficient airflow or an exhaust fan, so you don’t want to insulate too heavily. However the hot weather in Uruguay (especially along the coastal areas which always have a significant wind) is not stifling in the way the winter dampness is uncomfortable. This trade-off, in my opinion, is not enough to argue against insulation.
Standard new house construction involves two thick brick walls bonded with metal ties but separated by a gap of about 75mm. Although these walls are waterproofed, the cavity is rarely filled with insulation as would be the norm elsewhere. In some cases this is for reasons already discussed (they find it an unnecessary expense), but also because in certain areas ants have been known to eat most types of insulation material, and can even nest in it. One expat living in rural Colonia said he saw a 75mm layer of solid roof insulation hollowed out by ants so they’re not just a ground level threat either. One expat discusses the option of “structural insulated panels” (SIPs) as insects will not feed of the foam cores but they are still susceptible to nesting, and of course then there is the challenge of finding such specific products down here. Some have mentioned borate coating as a solution to these problems, others worry about health issues of using such chemicals.
What type of insulation is available?
If you are renovating and looking to improve (or install) insulation on concrete brick exterior walls there is expanded polystyrene sheeting readily available. The standard sheet size is 1200mm x 2400mm (8′ x 4′) and 50mm (2″) thick and depending on the building it can be attached to the inside or the outside of walls. For internal walls this process is done by attaching timber battens, fitting the polystyrene sheeting between them, plasterboarding over both, and then applying a plaster skim coat. To do this externally, the process is similar but instead of plasterboard they use expanded metal mesh that goes over the polystyrene and then several coats of cement render. The main challenge in insulating older buildings is the roof. If the existing roof doesn’t extend far enough this leaves little space for creativity. Keep in mind that little finishes like ensuring that seals around doors and windows are done properly can make a big difference over time.
In terms of insulation the so-called “sandwich” method seems the most straightforward. This is a double brick wall – the inside brick layer is covered with a mortar mix, then water-proofed with a tar-like goo, then covered in the mortar mix again, then a polystyrene sheet for temperature insulation, then the exterior brick wall, then the “mezcla gruesa” or thick mortar, and lastly the “mezcla fina” or thin mortar, which you can paint on. This method would be considered one of the higher quality insulation techniques. A waterproof membrane is also applied to the cavity surface of the inner brick layer before the outer layer is done.
As insulation isn’t the norm there aren’t a huge range of insulation products available. In rural areas sheets or rolls of fibreglass or rockwool are not available, although they have been using some rockwool cavity bats in Punta del Este construction (again, what is available and what is done in Punta del Este is not representative of the rest of the country – this area is an exception). In place of the products they are accustomed to, some expats have been creative in their insulation choices with expanded polystyrene sheeting and dense yellow polyurethane spray foam.