The ’30s house’ is one of the most sought after house types in our field (Haarlem area).
1930s homes have a lot of character and are often ago in neighborhoods and streets that are more spacious. They are often located on wider streets, have larger lots, and often have a back entrance. These homes are traditionally built with wooden floors and lend themselves well to being rearranged (remodeled) according to your own wishes.
But what do we know about this construction period when it comes to common defects? In this BLOG, you will find a tight overview of the common defects in construction from the
1930s and 1940s.
The cavity wall
1930s houses are known for the introduction of the cavity wall; instead of a wall consisting only of transverse bricks (a “stone wall”), a wall was introduced which consisted of a masonry outer wall, a gap of a few inches with air (for insulating purposes and to keep moisture out) and an inner wall. An excellent method until they wanted to insulate it about 70 years later….
After isolation
These types of homes are often post-insulated. Especially with cavity wall insulation, things go wrong remarkably often. This can cause moisture penetration, condensation from the inside or, for example, rising damp. Cavity wall insulation is the ‘quickest win’ to save energy costs, but also the biggest risk for structural defects. What you need to remember for now is: Cavity wall insulation = be alert for problems! Buy a home with cavity wall insulation? First, see what kind of cavity wall insulation was used. Of all the types of cavity wall insulation, EPS beads are preferred. Cavity wall insulation and pur foam is often bad news. Always get an architectural specialist who can best advise you on whether it is a good purchase or how to correct any defects caused by cavity wall insulation.
Moisture problems due to poor crawl space ventilation
There are vents in the exterior wall to ventilate the crawl space. What you very often find is that these are blocked (by planters, for example) or intentionally closed. (This sealing is often done because people think it will keep out pests). The result is moisture in the wall and in the crawl space cannot leave. This can cause beams to rot, or mold or fungus to develop in the crawl space and wooden structural floor.
Tip: Signs of a rotten floor are given when you feel play in the floor the floor bends with you. It is also possible that with a moisture meter you are measuring too high a moisture percentage at the bottom of the interior walls on the first floor.
Joints
Pay close attention to the joints from this construction period these can be of moderate to poor quality.
Oil tank
In these types of homes, there may still be an oil tank in the yard. It is then important to know whether it has been remediated and whether there is a Kiwa certificate for this.
Wooden Lintels
Wooden lintels may have been used above window openings. Wood has a greater coefficient of expansion than steel or concrete. The result may be that cracking has occurred or is about to occur. Also, if wooden lintels are not properly maintained, they will rot and this can also cause cracking to occur.
Sewer
In the past, vitrified clay sewer pipes were used. I can guarantee you 1 thing and that is that this one time no cracks or breaks you your house is literally in the shit. Important to know if these are there and if they are easily accessible to have a PVC sewer replaced.
Tiles
Pay close attention to the roof tiles, they may be worn or damaged. Sometimes there are still old ‘hollow tiles’ on the roof these do not seal optimally so that moisture problems could be or occur.
Lead pipes
There may be lead water pipes and/or lead drain pipes in the home.
Lead water pipes can cause lead poisoning. Lead drain pipes have the same bad humor as vitrified clay sewer pipes: they are guaranteed to fail you once and cause leaks. If you are remodeling and there are lead pipes somewhere, make sure you always replace them.
Elektra
There is originally old canvas (fabric) electrical wiring in these types of homes. This is old junk and should be replaced ASAP. This is because it can really cause short circuits and with it fires in your home.
Steel lintels
Do you think: ‘hey luckily I don’t have wooden lintels, I have steel lintels’. Error! There are many problems with this as well. In fact, steel lintels can oxidize (if not maintained in a timely manner). When this happens, they expand and cracks can appear in the exterior walls.
Concrete lintels
They didn’t start using these until the late 1930s. Cold bridge problems can occur in concrete lintels. Simple explanation: the wall is nicely insulated with cavity wall insulation but the concrete lintel above the window frame is not. This forms a ‘cold bridge’. A cold bridge attracts condensation. This can cause mold to form at the lintel. Also, the lintel may become subject to concrete rot. The steel reinforcement in the lintel has then started to rust, and will expand causing the lintel to crack and lose its load-bearing capacity.
Bearing frames
Frames that had a load-bearing function were still sometimes used in these types of older homes. If the rolling layer above the frame was longer than 1 meter, they had to be additionally supported and this was done by a sturdy supporting frame. It may be that over the years this frame has been replaced and a sturdy enough frame was not put back in place without additional help or supporting structures. The result may then be that cracks in the masonry (have) developed.
Wooden foundation piles
During this construction period, pine foundation piles were widely used. These posts are extra sensitive to bacterial infections and fungi. Spruce posts are less affected by this. The biggest problem with wooden foundation piles, however, is when they become dry due to varying groundwater levels. What can then occur is pile rot with all its consequences.
Wooden Floors
Basically, wooden floors were always used during this construction period. Here, then, wooden floor joists were used whose beam heads were anchored in the wall. Moisture rising in the walls can cause the post heads to rot and the beams to have to be replaced. However, fungus, mold, and woodworm are also common problems with wood floors. During purchase viewings we try to pay attention to whether the floor is bowing (which can indicate rotten beams), we try to measure moisture in the wall (moisture can indicate rotten beam heads) and we see if there is a crawl hatch available for us and/or a structural engineer to look into to see if everything is okay.