diff --git a/src/maploader/specials.cpp b/src/maploader/specials.cpp
index 240b0818bf..9393d4823a 100644
--- a/src/maploader/specials.cpp
+++ b/src/maploader/specials.cpp
@@ -127,7 +127,6 @@ void MapLoader::SpawnLinePortal(line_t* line)
 		line->portalindex = Level->linePortals.Reserve(1);
 		FLinePortal *port = &Level->linePortals.Last();
 
-		memset(port, 0, sizeof(FLinePortal));
 		port->mOrigin = line;
 		port->mDestination = dst;
 		port->mType = uint8_t(line->args[2]);	// range check is done above.
diff --git a/src/playsim/portal.cpp b/src/playsim/portal.cpp
index 6a0170111d..c080dc210e 100644
--- a/src/playsim/portal.cpp
+++ b/src/playsim/portal.cpp
@@ -540,7 +540,6 @@ unsigned FLevelLocals::GetSkyboxPortal(AActor *actor)
 		if (sectorPortals[i].mSkybox == actor) return i;
 	}
 	unsigned i = sectorPortals.Reserve(1);
-	memset(&sectorPortals[i], 0, sizeof(sectorPortals[i]));
 	sectorPortals[i].mType = PORTS_SKYVIEWPOINT;
 	sectorPortals[i].mFlags = actor->GetClass()->IsDescendantOf("SkyCamCompat") ? 0 : PORTSF_SKYFLATONLY;
 	sectorPortals[i].mSkybox = actor;
@@ -565,7 +564,6 @@ DEFINE_ACTION_FUNCTION(FLevelLocals, GetSkyboxPortal)
 unsigned FLevelLocals::GetPortal(int type, int plane, sector_t *from, sector_t *to, const DVector2 &displacement)
 {
 	unsigned i = sectorPortals.Reserve(1);
-	memset(&sectorPortals[i], 0, sizeof(sectorPortals[i]));
 	sectorPortals[i].mType = type;
 	sectorPortals[i].mPlane = plane;
 	sectorPortals[i].mOrigin = from;
@@ -586,7 +584,6 @@ unsigned FLevelLocals::GetPortal(int type, int plane, sector_t *from, sector_t *
 unsigned FLevelLocals::GetStackPortal(AActor *point, int plane)
 {
 	unsigned i = sectorPortals.Reserve(1);
-	memset(&sectorPortals[i], 0, sizeof(sectorPortals[i]));
 	sectorPortals[i].mType = PORTS_STACKEDSECTORTHING;
 	sectorPortals[i].mPlane = plane;
 	sectorPortals[i].mOrigin = point->target->Sector;
diff --git a/src/playsim/portal.h b/src/playsim/portal.h
index abffde16ba..164593daf6 100644
--- a/src/playsim/portal.h
+++ b/src/playsim/portal.h
@@ -193,6 +193,11 @@ struct FLinePortal
 	double mCosRot;
 	portnode_t *lineportal_thinglist;
 	FLinePortalSpan *mGroup;
+
+	FLinePortal()
+	{
+		memset(this, 0, sizeof *this);
+	}
 };
 
 struct FLinePortalSpan
@@ -238,6 +243,11 @@ struct FSectorPortal
 	double mPlaneZ;
 	TObjPtr<AActor*> mSkybox;
 
+	FSectorPortal()
+	{
+		memset(this, 0, sizeof * this);
+	}
+
 	bool MergeAllowed() const
 	{
 		// For thing based stack sectors and regular skies the portal has no relevance for merging visplanes.