Access via a hatch is necessary for the inspection of a wooden ground floor. If there is no or insufficient access, several elements, components, and/or sections of a crawl space will remain uninspected. Therefore, nothing can be said about the floors, the floor structure, the sewer system, the climate in the crawl space, and/or whether there is any asbestos present in the form of sewerage, waste, or similar materials. Full access to a crawl space is therefore essential. With insufficient or no access, you cannot inspect the foundation, sewer system, soil structure, or other unidentified structural features or defects below this floor level.
If the wooden floor is not insulated, living comfort can still be increased by insulating the floor from the crawl space.
If the floor is insulated, the insulation material may be cold-mounted to the floor boarding , which isn't ideal. If the crawl space is damp and poorly ventilated, this can cause problems. Condensation can also form between the insulation material and the floor boarding, but only if the top side is also vapor-tight. Such insulation is usually not 100% vapor-tight, and often the seams aren't fully sealed, allowing condensation to escape.
If the floor is insulated on the underside and the insulation material is installed with a (ventilated) space between the floor boarding and the insulation material, this prevents condensation from forming between the different materials. In our opinion, this is a correct application and installation with maximum efficiency. Insulation installed under the joists also has the same effect and function as installing it between the joists with a (ventilated) space.
The risk of wood rot in beams can never be completely ruled out. Several wood-destroying pathogens (such as brown rot) originate from the core of the wood and are often not immediately visible. To properly identify this, each beam should be hammered every 30 to 40 cm along its entire length.
You can check floor joists for wood rot, whether they are thick enough, strong enough, and stable enough to function as load-bearing beams. Also, pay extra attention to the foundation supports (benching) for wood rot, brown rot, or moisture in the joist heads due to rising damp from the foundation. The quality of joists deteriorates with age; the parts of the joists that actually "stick" into the wall cannot be seen because that would require removing parts of the joists or foundation.
Floor joists are supported by the foundation. If wood rot is detected at this support, we assume it is repairable and/or that a steel bracket can be installed under the joist to the foundation to take over its support function. If wood rot (or brown rot) is detected in the floor joists themselves, the cause and effect must be addressed. Only by addressing these defects can the precise extent of the damage often be determined, and a decision may be made to replace an entire floor joist or several. Replacing a floor joist is not easy, especially because it is cemented in on both sides.
If traces of active woodworm are found in the floor and floor structure, woodworm can further damage the beams and floor boarding and eventually even weaken the structure. Treatment is easily possible by yourself or by a qualified specialist. To prevent further spread, we recommend taking the necessary action as soon as possible. Also, seek further information about preventative woodworm control and prevention options.
If traces of inactive woodworm have been found in the floor and floor structure, it's possible that treatment has already been carried out in the past. It's also possible that the woodworm has left on its own due to changing conditions in the room.
If you suspect the presence of a longhorn beetle in your beams and/or floor boarding, one of the woodworms that can cause the most damage in the Netherlands is the longhorn beetle. Short-term treatment is always recommended if a live longhorn beetle is present. Treatment may even require replacement of parts of the beams in the worst-case scenario.
If you've checked your wooden floor and beams for woodworm or other wood-destroying pests and haven't noticed any, keep in mind that this is always just a snapshot. Depending on various conditions, such as climate and ventilation, brown rot can develop and spread quickly.
Floor joists are naturally supported by a foundation, and they can also be supported by one or more masonry piers . Such support provides greater stability and strength to the floor as a whole. Due to the span and the dimensions of the joist, this support would have been necessary. In itself, it's an excellent and well-functioning solution that can be retained. If masonry piers were not used for this support, but a less stable support, this may also work, but it should be checked periodically for strength and stability.
Wooden floor joists may also exhibit some sag, which can cause the floor to slope at the top or cause limited movement when excessive loads are applied. If the wooden floor joist(s) lack sufficient support at the supports and/or piers, this can easily be remedied by applying underlayment mortar.
The cost of a building inspection (up to 250 m²) is only €489 including VAT. We'll conduct a comprehensive building inspection and you'll receive a building report. Do you have any questions? We're happy to help and can schedule an appointment with an expert inspector right away if you wish!
