If you’re American or European, your exposure to building techniques is most likely limited to brick built or drywall buildings constructed with a mix of wood, steel and other materials. Perfect for your climate and geography, but to all intent and purpose, useless here. In the Philippines, concrete is king. End of discussion.
Can you use wood and framing? Absolutely, but why would you. In an area where humidity and rain are constant and termites abound, concrete rules. The cost factor alone, with wood being one of the most expensive materials to choose, and not readily available, makes the argument almost redundant. Then there is the issue of earthquakes.
The Philippines experiences these on a daily basis, situated as it is, directly over the ring of fire, with multiple active volcanoes spread across the islands. To build a home that is both typhoon and earthquake resistant, reinforced concrete offers the best results in terms of strength, longevity and cost. It is also one of the most flexible building materials in terms of design.
There are a few basic fundamentals that you need to adhere to when designing your home, and while some of these may not make immediate sense, there will come a time that you will sigh with relief at having done it.
Tips for Building Storm Proof Homes
Raise your house!
If your lot is already elevated you may question why this is necessary. It is. In the Philippines there is no real management for rain water or allowances for water flow. Storms can dump inches of rain in minutes and driving winds can push this water in directions that defy gravity. Your “island” can be submerged in ways you hadn’t foreseen. Usually, lifting your ground floor two or three courses of hollow blocks above the outside floor level will provide a large enough safety window.
Yes, steps can be a pain in the butt access wise, but dry is dry, and when the world around you is submerged, say a silent prayer of thanks.
Opt for a pitched roof.
Why not simply put a concrete slab up and be done with it, you may ask. A top concrete slab has a number of advantages over a pitched tiled roof, the most important probably being the facts that it is impervious to wind and will keep your home more insulated against the heat, that, and the fact it offers a great “deck” to sit on late afternoon and enjoy a beer. However, if you look around at larger homes here, what do you see. Pitched roofs everywhere. Why?
The main reason is water, or more specifically rain. Roof slabs have a tendency to leak, and not just a little. Waterproofing here is often sub-par and building techniques like casting slab and beam separately can greatly affect the finished products ability to resist water ingress. Secondly, water flow off is almost always underestimated and even when it isn’t, unique storm conditions can overwhelm even the best design. Remember the wind we mentioned? It can push water into a corner on top of the roof and overwhelm your drain pipes. Result. Potential flooding.
Thirdly, there is the weight issue. A slab adds dramatically to the stress placed on the walls and structure below, whereas the pitch roof doesn’t. There is also a safety issue, one you can choose to ignore if you so choose, of a large earthquake. Would you rather have roof tiles raining down on you or a six inch thick slab of reinforced concrete? Lastly, cost wise, the slab is far more expensive, construction wise, than a pitch roof. We always opt for tubular steel to erect rafters, trusses and purlins in our builds. The process is relatively cheap and quick, saving on time, labor and materials.
As some of you will be wondering, yes, a pitch roof, correctly angled and installed properly, can easily withstand a typhoon. Again, here, the materials used and construction method employed matter hugely, and will make the difference between staying dry or fetching your roof back, two blocks down, after the storm.
A last note on pitch. A flat roof, with no pitch, is far more likely to be prone to high winds. If you put up a carport or shade for a pool, keep this in mind.
Smaller is better
When it comes to windows, we all love big expanses of glass, offering an uninterrupted view of the scenery that surrounds us. With proper design, you can install large sheets of glass here, with relative safety. We usually design for multiple smaller panes, purely for safety reasons.
If you opt for thick laminated glass on larger windows, wind is not the issue during storms, but rather the projectiles the wind carries. Remember the roof scenario. Your neighbor may not have exercised as much caution fitting his roof, and the wind will pick up entire roof sheets and deposit them where it chooses, often a mile or more away from the initial pick up point.
The damage these projectiles can cause is considerable, especially in the event of a super typhoon (winds in excess of 200 km/h) and while these super storms are the exception rather than the norm, you will experience one at some point if you live in Asia.
Where possible, our advice is to opt for smaller windows, and cover large areas with lots of smaller panes, rather than a single sheet of glass. This way, the frames for the glass offer protection, and if you do happen to get hit, it’s going to be minimal damage, rather than having a gaping hole appear in your living room, mid-storm. An architect worth his salt, will, based on your lot layout, be able to advise you on where you can safely install larger windows.
Drops in patios and entrances
While this may seem glaringly obvious we recently saw a foreigner run tiles from his living room directly out onto a small porch outside his front door, all at the same level. Any outdoor surface adjoining exterior doors and sliding windows needs to be dropped a minimum of two inches below the indoor level. If the area is exposed to copious rain, consider increasing that drop.
Even areas that enjoy cover, like porches, can still get inundated with water if the prevailing wind blows in the right direction, forcing large amounts of rain into areas water wouldn’t normally reach.If you don’t have a small “ledge” to catch this water, expect to be mopping up (a lot).
Installing Run Off’s
The water that collects off your roof during a storm can be the very reason your home floods and this applies to both flat and pitched roofs. Depositing large volumes of rain water via downpipes can overwhelm the grounds ability to channel away the excess water, and it can rapidly build up to levels that threaten your home. Luckily, there are simple and easy solutions to this.
Installing a simple network of sunken drains around your home is cheap and quickly done. Allow for grates to access these from time to time for cleaning and if possible, direct the flow towards the nearest road. By law, in the Philippines, the neighbor that abuts you has to allow for your runoff, in the same way you need to allow for your neighbors.
Keep in mind, that if you wall your entire property in, you are potentially creating a “swimming pool” if you don’t make provision for the runoff from large storms, and not piping water from your roof into these runoff’s will exacerbate any potential flooding.
Consider Removable Shutters for large Windows
If installed during the building process, shutters (either removable or roll down) placed over or above large windows will ensure your house is completely secured against heavy winds and rain. We often utilize a system of tubular lip channel placed above and below the window’s top and bottom edges. This allows for a sheet of 3/4th’s plyboard to be easily placed in front of the window, secured, and then easily removed after a storm has passed.
Precut these marine plyboard sheets to fit each of your windows, varnish them, and store after use. Properly treated, they can and do last for years, and can used over and over. A double coating of polyurethane based sealant will provide adequate protection for the wood.
Treat all exposed wooden surfaces
Ensure if you’ve opted for wooden doors, that these are treated properly prior to hanging them to ensure the wood cannot absorb moisture and that it is resistant to termites. If your door and window frames are wooden, these will need to be treated in the same way. Apply a wood sealant first, then apply a layer of polyurethane based varnish to seal properly. Repeat this coat on an annual basis to stop water being absorbed by the timber.
Doors should be treated annually, but windows can be left for three years. Do make frequent visual inspections of wooden fixtures to ensure termites or ants haven’t found a soft spot in the wood.